Sunday, September 18, 2016

Black Powder or Nitroglycerin - what made the pressure cookers explode?

Part 2 - the ambiguous New Mexico experiments



Please read also Part 1 - the nitroglycerin-contaminated soup can lid

Days after the Marathon bombings a crowd of TV journalists and explosive engineers flocked into the desert of New Mexico. The New Mexico Institute of Mining and technology, shortly New Mexico Tech, is recognized as home to some of the top explosives minds in the world. For each media crew the experts conducted a simulation of the blasts at Boylston Street. They filled a pressure cooker with an explosive and a couple of metal nuts, let it explode and recorded the explosion.

Three of these experiments are available on video:

1 - CNN, aired in April 2013
2 - KOAT (a New Mexico based TV station), aired in April 2014
3 - Inside Edition, aired in April 2015

Clip 1 and 3 were obviously recorded on the same day in April 2013 because the set-up is exactly the same. The wooden shield left of the pressure cooker and the items in the background are identical in both clips. Moreover the length of the shadows shows that Clip 3 was recorded around midday while Clip 1 was taken in the afternoon, i.e. after Clip 3. The set-up in Clip 2 is different, and it was probably recorded after the other two.

The nature of the explosive is not revealed, but it can easily be concluded that it was black powder: it is ignited by heat, not by a shock wave (you can see the smoldering fuse cord), so it's not a high explosive - and it produces the white smoke typical of a black powder explosion.

Dr. Van Romero is the vice president for research at New Mexico Tech and a demolition expert. He guided the various reporters through the experiment. Romero became famous when he stated on the day of the 9/11 attacks that there must have been explosives placed inside the WTC towers to take them down. He retracted this comment a few days later in favor of the official theory that the fire caused by the plane crashes made the towers collapse.

In Clip 3, chronologically the first experiment, there is a stunning lack of damage by shrapnel in the plywood shields.

According to Romero, this was because the pressure cooker was placed upright.

Romero: "Everything went straight up. Most likely what happened in Boston was that it was turned on its side, so everything shot out into the street."

Indeed Clip 3 shows that the blast sends the lid vertically upwards, and this is the reason why the plywood shields were not hit by the metal nuts.

Also - most important - the bottom part, the pot, is not shredded, but still in one piece. Romero has it in his hand. The next picture shows that it is still at the same place after the explosion (blurry, but distinctly recognizable below the white smoke):

Clip 1 is taken only a few hours later, and Romero has reacted to the problem. Now the pressure cooker is turned so that the lid is pointing to the side.

And this time the nuts indeed have pierced the plywood.

The most puzzling thing is that the pot this time has been shredded into sharp-edged pieces, as opposed to Clip 3, despite identical conditions (with the exception of the alignment of the pressure cooker).

In Clip 2, the pressure cooker is turned onto the side just as in Clip 1. And again there seems to be shrapnel from the bottom part flying around. But a closer examination of the footage of the explosion shows that Clip 2 is not genuine at this point. Here is a series of snaphots of the explosion. In snapshot #6, suddenly a plywood shield emerges on the right side which was not there before.

This video segment ist obviously composed of two different videos and a cross-fade between them. Subsequently, a piece of shrapnel, allegedly from the pressure cooker, flies towards the shield.

So the manipulated Clip 2 seems to corroborate Clip 1 (but contradicts Clip 3) in that the pot is shredded into pieces by the explosion.

The ambiguous results of the experiments and the obvious manipulation of Clip 2 raise the question whether the black powder used in the New Mexico experiments was really powerful enough to shred the bottom part into pieces - or if it only blew the lid off, slightly deforming lid and pot, but not shredding them.

Snapshot #1 of Clip 2 is a valuable hint that the latter ist true.

It shows that the pressure wave of the explosive leaks via the weakest point which is where pot and lid are screwed together. The bottom part is not shredded, it remains in one piece. Obviously the black powder utilized in the experiments is not powerful enough to shred the pot.

This is highly relevant for the Marathon bombs because they sent their destructive pressure wave, nails and ball bearings included, in all directions, not just through the lid. It hit people nearby in a 360 degree angle around itself. Van Romero is ill-informed by stating that the blast "shot out into the street". It shot into all directions.

The final conclusion is that the New Mexico experiments actually show that black powder was not able to create the powerful and destructive explosions at the Marathon. The pressure cooker must have been filled with a stronger explosive, maybe a nitroglycerin-based smokeless powder. As the conviction of Dzhokhar Tsarnaev is based on the (probably right) assumption that his bag contained black powder, this renders the assumption fallacious that his bag caused the deaths and injuries of people at the Forum.

Sunday, August 21, 2016

Nice: what happened in front of the Hotel Negresco?

The famous Negresco hotel is situated right in the middle of the two locations I featured in the last two blog entries, the Westend hotel and Point Gambetta. There are contradictory clues about what happened on the street in front of the Negresco when the truck passed by, and this blog post is a compilation of these clues.

The location was mentioned at first by chief prosecutor Francois Molins on July 15th. According to the Telegraph he said
"the terrorists fired several rounds at three police officers, who were outside l'hotel Negresco. The police officers followed the lorry which managed to go another 300metres. They managed to neutralise him by shooting by the Palais de la Medinterranee."
This quote is not 100% correct and omits a detail - Molins said that the officers at the Negresco shot back at Bouhlel before pursuing the truck:
"Le terroriste a tiré à plusieurs reprises sur trois policiers, à hauteur de l'hôtel Negresco. Les policiers ont répliqué et ont poursuivi le camion, qui a cependant réussi à rouler encore sur 300 mètres.
Les policiers sont parvenus à le neutraliser par des tirs à hauteur du Palais de la Méditerranée."  (Source)
More details on the shootout are not available. Just to the contrary, a timeline allegedly compiled by Sandra Bertin of the Nice municipal police and leaked to the media doesn't mention any incident at the Negresco, thereby suggesting that no shootout happened at all: 
Vingt-deux heures trente-quatre minutes et trente-six secondes : visualisons que le véhicule se dirige alors vers la chaussée qui est emplie de piétons, en faisant de nouveau une embardée. Ce décroché survient à hauteur de l’intersection Promenade des Anglais / Rue CRONSTADT---
Visualisons à vingt-deux heures trente-quatre minutes et trente-sept secondes que le véhicule qui a emprunté la chaussée se retrouve parmi une foule très dense et que de nouveau de multiples embardées sont réalisées pour tenter de faucher le maximum de personnes.
Vingt-deux heures trente-quatre minutes et quarante-neuf secondes visualisons que le véhicule emprunte de nouveau le trottoir, en poursuivant toujours sa progression en direction de l’Est et en fauchant au passage des dizaines de piétons ainsi qu’un stand de marchandises ; le véhicule se situe alors face au 27 promenade des Anglais.  
A simple calculation shows that according to this timeline, the truck must have passed the Negresco at 22:34:44 with a speed of at least 45 km/h. Not only is a shootout not mentioned, it seems also unconceivable that Bouhlel steered the truck, running over people with 45 km/h and simultaneously shot at the police.

Moreover, Sandra Bertin, the alleged author of the timeline, seems to contradict herself by saying in an interview to the Journal Du Dimanche:
Le poids-lourd se retrouve finalement face aux policiers nationaux, qui tirent et le neutralisent. Il est 22h34. 
So the truck and its driver were "neutralized" at 22:34 by shots of policemen. This matches Molins' statement that there was a shootout at the Negresco, because the only other shootings happened in front of the Westminster Hotel at 22:35 (according to the said timeline) and at the final position in front of the Hyatt Hotel, which happened not earlier than 22:36.

I have stressed the dubious (Le Monde: confusing) nature of this timeline in the previous blog entries, and the omitted Negresco incident certainly increases this impression. It has still not been confirmed by Sandra Bertin or any other spokesperson of the municipal police, so the conjecture that it was not written by her is absolutely justified.

The title photo is from the intersection with the Rue de Rivoli, right at the Negresco. It shows a demolished street lamp, indicating that some form of accident happened here. A video taken from the sidewalk in front of the Negresco shows a police car with blue light across the street. 

The video and the snaphot are too blurry to say what exactly is going on there, but the footage certainly indicates that something extraordinary did happen at this location. The truck might also have lost its front plate right here.

Evie and Tim Timotheou from Adelaide, Australia, might have witnessed the incident at the Negresco. They resided in the Westend Hotel, which is very close. They heard a "thud" or "big bang" and then, after a few seconds, gun shots.
Then, "I heard an almighty thud and I wondered what it was," retail sales manager Evie tells WHO. "Seconds later I heard gunshots. We saw people running in different directions." (Source)
"We’re probably about 20 metres away and the whole promenade is now in lockdown. We were on the promenade, the fireworks were going for about half an hour and as soon as the fireworks finished, we started walking back to our hotel room and literally there’s a big ‘bang’ — probably about 30 seconds later there were gunshots." (Source)
Which gunshots did the couple refer to? Probably not from the Hyatt scene, which is 250 meters away - the Timotheous claim it was only 20 meters. There was also no "almighty thud" before the police started to shoot at the standing truck. For similar reasons, the two shots from the police at the Westminster hotel, as documented in the Gutjahr video, don't come into consideration. A shootout at the Negresco however makes sense because it is in the direct vicinity of the Westend, and the thud might have been caused by the truck when he rammed the street lamp.

Finally it should be noted that the truck was detected on surveillance footage of July 12th and 13th in front of the Negresco. On both days, Bouhlel stopped there and activated the hazard lights for a while before moving on. This seems to indicate that the Negresco played an important role in his plan.

Bottom line: there is quite a lot of evidence that the truck was stopped by the national police at the Negresco, followed by a shootout - and that it moved on afterwards. But officials are cloaking the incident in secrecy - for how long?

Sunday, August 07, 2016

Nice: what happened at Point Gambetta?

"Point Gambetta" is the intersection of the Promenade des Anglais with the Boulevard Gambetta, about 600 meters west of the final position of the truck. Exactly here the street was blocked by barriers and car traffic was diverted. It was the beginning of the "pedestrianized" zone of the Promenade. More than three weeks after the attack, the details of the truck's path are still not clear and in part contradictory. Point Gambetta is one of these problematic details.

According to Le Monde, the street was blocked by the municipal police, with two policemen, one car, metal barriers and plastic elements. Libération published a photo taken minutes before the attack, apparently during the fireworks (people are looking into the sky). There are metal barriers in the foreground blocking the way on the street. The incoming traffic is diverted to the left.

Libération writes:
Au moment où Lahouaiej Bouhlel contourne le barrage de Gambetta en montant sur le trottoir, poursuivant ainsi son carnage, les premiers hommes de la police nationale sont placés au cœur de la zone piétonne, à 370 mètres plus à l’est, près de l’hôtel Westminster.
 "contourne le barrage de Gambetta en montant sur le trottoir" implicates that the truck was driving on the street when he approached Point Gambetta and made a swerve to the right there to continue his ride on the trottoir. Unlike the street, the trottoir was not blocked by any obstacle. Sandra Bertin has confirmed this version to the Journal du Dimanche: "Il contourne le barrage de la police municipale." Bypass, no breakthrough.

Stunningly in an official timeline published by Frédéric Ploquin in Marianne and accredited to - but not confirmed by - Bertin, the swerve isn't mentioned and the truck was driving on the trottoir already when it reached Point Gambetta:
Vingt-deux heures trente-quatre minutes et trente secondes : visualisons que le véhicule circule encore plus vite, toujours dans la même direction ; sa vitesse pourrait être estimée à environ 90km/h. Toujours sur le trottoir de la Chaussée Sud, le camion écrase et percute de très nombreuses victimes, tout en continuant sa course folle.
Vingt-deux heures trente-quatre minutes et trente-six secondes : visualisons que le véhicule se dirige alors vers la chaussée qui est emplie de piétons, en faisant de nouveau une embardée. Ce décroché survient à hauteur de l’intersection Promenade des Anglais / Rue CRONSTADT---
Rue Cronstadt is 100 meters east of Point Gambetta. With a speed of 90 km/h, the truck must have passed Gambetta at 22:34:32, driving on the trottoir the whole time ("toujours"). This blatant contradiction has obviously not escaped Le Monde who expresses confusion about the timeline.

There are also a couple of photos taken at Point Gambetta after the attack - the title photo is one of them, showing the trottoir between Boulevard Gambetta and the Hi Beach club. These pictures are suitable to fuel the confusion because they show some apparently dead victims on the trottoir, covered by blue cloths. They seem to confirm that the truck had mowed down people on the trottoir when he approached Point Gambetta, thus confirming the timeline in Marianne and contradicting Libération, Le Monde, and Sandra Bertin.

A clarification is urgently needed.

Tuesday, August 02, 2016

Nice: what happened in front of the Westend Hotel?

The Westend Hotel is situated between the Negresco and the Westminster Hotel, just opposite the Blue Beach restaurant. The begin of the Gutjahr video, shot from the Westminster Hotel, shows the truck turning into the street after obviously travelling on the trottoir for some time. The seconds immediately prior to the Gutjahr video - when the truck passes the Westend Hotel - are meticulously covered in a timeline allegedly written by Sandra Bertin and transmitted to the national police who forwarded it to the magazine Marianne:
22:34:49  You can see the vehicle going on the trottoir again, continuing its ride to the east and mowing down tens of people as well as a kiosk; the vehicle is then situated across 27 promenade des Anglais.

22:35:04  You can see that the driver is apparently about 30 years old, has short brown hair and wears dark clothes; the individual is alone in the cabin.

22:35:07  The truck turns back onto the street and continues his course.

22:35:15  You can see an agent of the national police running behind the truck.

22:35:20  You can see an agent of the municipal police running behind the truck; the vehicle is situated at the intersection of the Promenade des Anglais and Rue Meyerbeer.

The last three occurences are covered in the Gutjahr video and thus enable to pinpoint its beginning at 22:35:05. The lights of the allegedly mowed down kiosk are also to see shortly at 0:03, at the right border above the zebra stripes:

Judging from this snapshot, the kiosk seems to be working, not mowed down. There is enough leeway between the kiosk and the quaywall. The truck must have passed behind it.

80 meters further to the west there is a pergola on the trottoir blocking the way. So the truck must have entered the trottoir behind the pergola. These 80 meters are situated exactly in front of the Westend Hotel. The following diagram covers the path of the truck in this phase.

google maps

Each rectangle designates a position of the truck per second. A, C and D are the positions of the truck at the respective times based on the timeline of the alleged Bertin report and, in the case of D, on the Gutjahr video. The speed at the last six seconds is about 15 km/h, corresponding to the Gutjahr video. The time of Position B is extrapolated from C and D. The red rectangles are interpolations per second.

The diagram shows that the truck needed 12 seconds for the 70 meters from A to B, corresponding to a speed of about 20 km/h. This throws doubts on the claim that it "mowed down tens of people" because at this slow speed most people should have been able to run away or go out of its way.

If the driver had accelerated to 50 km/h, a speed certainly sufficient to kill lots of people, he would have bridged the distance between A and B in 6 seconds, as the next diagram shows:

google maps

So the question is not only why so many people were not able to avoid the truck driving with 20 km/h, but also why the driver didn't speed up on the trottoir to cause maximum damage.

At this point, it should be noted that Sandra Bertin told the Journal du Dimanche that the police neutralized the driver at 22:34. This is obviously at odds with the report and justifies the question whether it was really drafted by Bertin herself - or if it is a "redacted" version of the national police.

There are only a few pictures of this crime scene available, the title picture is one of them. It shows the location only seconds after the attack. It has been taken by Evie and Tim Timotheou who resided in the Westend hotel across the street. They recorded a short video, but unfortunately it doesn't run, so we have only this snapshot.

Evie&Tim Timotheou
As blurry as it is, the picture shows people hurrying away, but no bodies or injured people on the ground, let alone "tens of people". It doesn't show any first aiders caring for people on the ground either, as you would expect.

Here is another picture, taken a few minutes after the attack:

Again, there are no dead persons on the ground visible. This is further evidence that the truck driver did not "mow down" people here. It increases the impression that there is something not right with the report - and that it should be taken with a grain of salt until Sandra Bertin confirms that she actually wrote it.

Wednesday, July 27, 2016

Nice: When exactly did the terror attack happen?

Update July 30th: the question can be considered as solved. A video covering the crime scene from 300m distance confirms that the fireworks ended at 22:19. At 22:36 it shows people on the Promenade suddenly fleeing from somewhat. At 22:56 and 23:12, the streets are emptied.

So the video confirms that the time of Sandra Bertin's report, 22:35, is the time of the terror arrack. And it belies Richard Gutjahr's claims that it happened 23:07 or "shortly after 23:00". Gutjahr has meanwhile corrected the time from 23:07 to 22:35 (see first update below), but the video belies also his new claim that the attack occurred during the fireworks.

Update July 28th: in a recent interview, Richard Gutjahr has surprisingly changed his account. See below.

Sandra Bertin (AFP)

Two weeks after a truck killed 84 people in Nice by driving over them, the exact daytime of the terror ride is still not clear. This is most remarkable because the incidence was witnessed by thousands of people and authorities and the media ought to be able in the meantime to report the time of the crime up to the minute. But media reports in the immediate aftermath vary from 22:30 to shortly after 23:00, and the uncertainty hasn't improved since. Here's an excerpt:

22:30  Valery Hache, AFP photographer
           Nice Matin
           Die Welt 
           Washington Post

22:30-23:00 Le Figaro

22:45  New York Times

22:45-23:00  Le Monde

23:00  Spiegel

23:07  Richard Gutjahr, ARD

The last source, the German TV journalist Richard Gutjahr, is the most reliable one insofar as he was in Nice, witnessed the last seconds of the terror ride from the balcony of his hotel room and filmed it with his mobile phone in a now famous video. He probably extracted the time from the metadata of the video.

All sources agree that the truck was going very fast, so it is incomprehensible why Le Figaro and Le Monde report a time span of 15 and 30 minutes. There are also countless private witness accounts, most of them pinpointing the attack at around 23:00.
So far, this hotchpotch has not been clarified by any official, no police president, no mayor, no prosecutor and no politician. The world had to wait for a medium rank police officer to learn of more details. Sandra Bertin from the Nice police department is responsible for the surveillance footage and hit the headlines by uncovering a row between the national government and the local law enforcement. She claims, among other things, to have been urged by the interior ministry to destroy crucial surveillance footage, which she refused to do. Instead she went public in an interview with the Journal du Dimanche and revealed details, finally:

Je me rappellerai toute ma vie de cette heure-là : 22h33. J’étais devant les écrans du CSU avec les équipes. Nous recevons alors des policiers municipaux positionnés sur la Promenade le signalement d’un camion fou. Nous récupérons tout de suite son image à l’écran et nous demandons son interception. Le camion était lancé à 90 km/h, sans phares, sans qu’on l’entende à cause du bruit. Il contourne le barrage de la police municipale. Les équipes n’ont pas pu l’arrêter. On ne crève pas les pneus d’un 19 tonnes avec un revolver! A ce moment-là, d’autres policiers municipaux sont en civil dans la foule, qui se retrouvent face à lui. S’ils avaient été armés comme nos collègues de la police nationale, une de nos revendications, ils auraient pu le stopper. Le poids-lourd se retrouve finalement face aux policiers nationaux, qui tirent et le neutralisent. Il est 22h34.

So she basically says that the truck's terror ride began at 22:33 and ended at 22:34. Two days later, Le Monde published excerpts of her report, leaked by the national police and causing confusion at the newspaper.

Le premier policier cité est national, et il court après le véhicule : « Vingt-deux heures trente-cinq minutes et quinze secondes : visualisons un agent de la police nationale à pied courir derrière le camion. » Puis c’est au tour immédiatement d’un agent municipal : « Vingt-deux heures trente-cinq minutes et vingt secondes : visualisons un agent de la police municipale à pied courir derrière le camion ; le véhicule se situe alors à l’intersection de la promenade des Anglais et de la rue Meyerbeer. » C’est-à-dire au niveau du premier point de contrôle tenu par la police nationale.

The said intersection (Promenade des Anglais/Rue Meyerbeer) is exactly the location captured in the Gutjahr video, i.e not far away from the final position of the truck. But there is a yawning 32-minutes discrepancy between Bertin's 22:35 and Gutjahr's 23:07.

So what's going on here? It's Bertin vs. Gutjahr. We have a 22:30+-5 minutes version and a 23:00+-5 minutes version. It appears that one of them must be utterly wrong. This is most astonishing because Gutjahr is a professional journalist and Bertin is a professional video analyst.

One circumstance might help to clarify the confusion: the fireworks. All media reports and private statements agree that the attack occured shortly after the fireworks ended, ranging from five to fifteen minutes afterwards. The determination of the end of the fireworks might verify either Gutjahr or Bertin.

Gutjahr himself says that the fireworks lasted from 22:15 to 23:00. However, there is a video of the complete fireworks which lasts only 18 minutes. Gutjahr probably included the preparations and made a rather rough estimation. So 22:15 seems to be a reasonable lower bound for the begin of the fireworks. Adding the 18 minutes duration of the fireworks video and the 5 minutes minimum until the attack delivers a lower bound of 22:38 for the attack. The fireworks were certainly finished before 23:00, so Gutjahr's 23:07 is a reasonable upper bound for the attack.

The bulk of evidence seems to validate Gutjahr and falsify Bertin. But Bertin's report is most detailed and based on primary evidence - the surveillance videos - so it looks odd that she could be so wrong.

Or is it possible that both Gutjahr and Bertin are right; that they are talking about different incidences; and that the official narrative has to be rewritten? If so, Le Monde sits on a bombshell and ought to tell the public more about Bertin's terror timeline  - soon.

Update: In a recent interview, Richard Gutjahr all of a sudden has changed the time data of his early reports: now he claims he filmed the truck at 22:35 when the fireworks were still ongoing.

Having initially wanted to produce a Snapchat story of the festivities, Gutjahr was stood on his hotel balcony filming the fireworks at 10:35pm when he noticed people running and screaming in the street below him.

"I saw something was wrong – something just didn't fit the image," he said.

"I happened to have my camera in my hand because I was still Snapchatting the fireworks, so not knowing what to expect, I turned the camera from vertical view to the horizontal position and used the phone's regular camera to film. I didn't want this to be on Snapchat."

It is absolutely certain however that the fireworks were finished when he took the famous video footage. First, there is no firework noise audible in the video. Second, there is a video of the end of the fireworks showing that no panic has erupted at this point. Third, it is known from another video that a rock band was playing just when the truck ploughed through the crowd - the band certainly didn't start before the fireworks were finished.

So why did Gutjahr change his account?

Thursday, May 26, 2016

Black Powder or Nitroglycerin: what made the pressure cookers explode?

Part 1 - the nitroglycerin-contaminated soup can lid


I can’t believe we are excluding explosives as expertise in this case - with this exclamation Judy Clarke protested the lack of interest on behalf of the prosecution for the nature of the explosives used in the Boston bombings at a pre-trial status conference in June 2014. The prosecution complied with her request and summoned David McCollam as an expert, a "chemic forensic examiner assigned to the Explosives Unit" of the FBI. He testified on March 26, 2015. You can download his statement here.

After talking about his career, credentials, and current job McCollam is asked to explain explosives in general. He makes a distinction between high explosives, like TNT, C4, dynamite or nitroglycerin, and low explosives like black powder or, notably, smokeless powder - we'll come to that later. He explains that low explosives have a detonation velocity below the speed of sound, whereas the velocity of high explosives is much higher than that mark.

He is then asked what residues of explosives the FBI found at Boylston Street and in Watertown and states that it was "low-explosive, pyrotechnical, firework-type material", i.e. the black powder type. He doesn't say if any other explosives, like smokeless powder or high explosives, were found at the bomb sites, and he's not asked for that - we'll also come to that later.

He is then asked if traces of the low explosive used at the Marathon were found in the Norfolk Street appartment, which he confirms.

In the cross-examinaton defense lawyer Timothy Watkins first asks him for some places where the black powder was found, like gloves etc. After that, he introduces a FBI photo showing the content of a drawer in the Norfolk appartment, concentrating on a lid detached from a soup can with an adhering black substance. And now the testimony takes a surprising twist:

For the first time the public here learns of high explosives in relation to the bombings - and it is the defense bringing the subject on the table, not the prosecution! Another one of these weird moments at the trial - what is happening?

A second look reveals that Watkins has established a contradiction between McCollam's statement in the direct examination - that smokeless powder belongs to the class of low explosives - and what he admits here, i.e. that nitroglycerin, a high explosive, is part of a "double-based smokeless powder". A little research reveals quickly that the "double based" is crucial:
From the aspect of the bomb technician, it is most important to understand that a single-based smokeless powder will only function as a low explosive. However, double and triple based smokeless powders may function as a high explosve, by initiating them with a detonator rather than a heat source. If used in this manner, they may achieve a velocity of detonation (VOD) of approximately 15000 ft/s, similar to dynamite.

Paul L. Laska: Bombs, IEDs, and Explosives
Watkins doesn't go deeper into the subject. It is all the more interesting that the day before Miriam Conrad already showed a similarly keen interest in the can lid during the cross-examination of Christopher Derks, a FBI agent who participated in the search of the Norfolk appartment:

This raises some interesting questions:

Why did the prosecution ignore this piece of evidence?
Why was the defense eager to pick it up instead?
Why did McCollam classify smokeless powder as a low-explosive in the initial examination when in fact it might belong to both of the categories, depending on the composition - especially as a high-explosive variant was found in Tamerlan Tsarnaev's home?

A fourth question may help to solve this riddle: has this nitroglycerin/ethyl centralite substance, the high-explosive double-based smokeless powder, been found at the bomb sites?

The fact that McCollam testifies that "low-explosive pyrotechnic material" was found at Boylston Street doesn't mean that no residues of high-explosives were found. He is not being asked for and doesn't explicitly exclude it. It appears that he knows that smokeless powder was found there, but fiddles around with its high-explosive nature to downplay its significance and the possibility that there were different bombs involved - other than the firework-powder filled backpacks of the Tsarnaevs. But Watkins doesn't let him get away with this play.

It should be noted that in the first reports after the bombings smokeless powder was mentioned as a probable explosive, alongside black powder (Daily Mail, NBC, and others).
Dzhokhar Tsarnaev's bag was not the black nylon backpack the FBI initially searched for. Video footage shows that his bag didn't contain a pressure cooker. I have argued on this blog that it was impossibly the epicenter of the second bomb. The nature of the "real" bomb seems to become increasingly clear: most probably it was a pressure cooker filled with high-explosive smokeless powder based on nitroglycerin, contained in a black backpack, and exploding on the patio of the Forum restaurant.

Does the can lid in the Norfolk appartment prove that the Tsarnaevs were involved in the "real" high-explosive bombs? No, not at all. It might have been planted there by the same people who want to make the Tsarnaevs the patsies for the Boston bombings. The prosecution has provided no evidence that the brothers acquired smokeless powder on any occasion.

In the next blog entry - Part 2 - I will deal with the question if the black powder that was presumably inside the Tsarnaev bags would have been able to have the devastating effect of the Marathon bombs.

Sunday, May 01, 2016

Causa Tsarnaev: testimony of Michelle Gamble, March 30, 2015

This is the transcript of the testimony of FBI photographer Michelle Gamble, including initial sidebar, direct examination, cross examination, re-direct examination, and re-cross examination. It was released on April 26, 2016, as part of the trial transcript of March 30, 2015.

An analysis of the testimony is here.