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Tiny pieces of shrapnel may provide some of the biggest clues in the hunt for the Boston bomber but it was not long after the blasts.
That we heard another piece of key evidence would be the video of the explosions themselves.
Including the white smoke seen rising after the explosions that tells you something.
Experts say it suggests that local products and not military grade explosives.
Were likely used.
Also some large pieces of the metal flying -- spot shadow of the here.
-- just reported on how we now believe pressure cookers were used to build these bombs.
And the devices may have been placed in black duffel bags possibly put on the ground or in the trash cans.
My next guest is one of the world's foremost explosives experts.
First working on an army bomb disposal as an army bomb disposal technician and that is a special agent with the FBI.
He sees as some of the investigations in which he took part.
The 1983 bombing of the US embassy in Lebanon the downing of pan am flight one O three over Lockerbie Scotland which has brought down by a bomb.
And the 1993 bombing of the World Trade Center.
Tom -- is now professor of safety security and emergency management at eastern Kentucky university -- Tom we're very grateful to have you today.
And have your expertise.
Along with you -- I mean is it is it like finding a needle in the haystack to try to find evidence.
Of who did it as you try to recreate.
Megan thank you very much for -- for having me be here today if it is absolute pleasure.
For finding in the needle in the haystack maybe yes maybe you know The -- the good thing is that.
We are rove actually in an urban environment and there is a lot of buildings around and other materials that saw some of this this evidence.
Old as it -- -- -- through the pavement.
And it will love it will be filed the agents world will go in and sort conducting -- crime scene investigation.
Defined even the most my new pieces all of evidence and if that wonderful we called -- and -- and send to the wire report.
And in the -- worried the the forensic.
Will look at these pieces all debris and then start making -- conclusions as to what the device consisted -- How do you I can understand how you could piece together what was the bomb made of how did it work how was it detonated and so on what how we were told.
It in the pan am 103 bombing which helped investigate that it was -- thumbnail sized piece of evidence.
That led to the identity of the bomber I mean how can that be how can you get to the identity.
From the remnants of the -- What sometimes and in pan am 103 the that fragment of the circuit board.
That with a timer that X detonated the device is so generically we're not generically and it's so specific.
That you can relate that back to a very specific -- Horry a series -- -- if you will to the exclusion of up anything else it is just like -- fingerprint and that's what we call a bomber's signature.
And I'm I feel certain that in these devices they may not be that that specific Megan but they are will be a certain bomber's signature.
In these devices -- what I mean the bomber's signature in these devices is similarity in component between the two.
And then the the investigators.
In the laboratory will will start looking at.
Databases are previously exploded devices not only in the United States but but worldwide.
And and cast that -- out there to say as anybody in any form of law enforcement.
Seen anything like this before have these components been been used is it.
Of previous devices and and then if that's representative -- previous devices.
Then we got maybe have a -- and all of investigation to go toward those individuals that were responsible if they were in fact identified.
Let -- underside let me ask you just -- -- -- they'll ask you about that the bomb blasts.
There were two.
And -- they're caught on tape at least the aftermath of the blast is caught on tape you can here and you can see the smoke.
It you know to -- expert like you is that in and of itself is that evidence -- it tell you anything.
If it does as a preliminary evidence and any.
Home and we're talking about the -- -- that the explosion and that will be confirmed in a laboratory.
Initially looking at this at the smoke.
That this is what killed.
It tells it what it it could be and also conversely what it is not what it could be is an improvised wolves one.
Number two it could be a low explosive that the people refer to as as gunpowder.
And the number three it could be a commercial explosive why dynamite.
Only other side of the color of the smoke tells me that it is north.
-- caught or a military -- receive for product and other works and military top the crawler.
It's already been helpless you know how does that help us get -- answers if we know that.
Well it it doesn't initially it it it actually has absolutely nothing to do with the investigation initially calls all of that is mutual.
And an actual forensic examination is required.
In the laboratory to determine exactly what type of explosive that was -- -- you -- and when we deter.
I don't wanna start of that did you have any thought in looking at these.
You know any any -- -- anything based in your experience.
About whether these -- -- they detonated remotely there's some there's been since some speculation possibly by cell phone.
They -- there's no way to -- by by just looking at them.
All I mean I can speculate just as well as as anyone else and my speculation without any tree of of of evidence.
Is that they were -- logically -- a time device.
In as much as you have to devices that or quoting within let's say fifteen or so seconds I'll -- chip.
As you look at this time is it is it clear -- you.
Well I mean we we know it's an act of terror and the president's call -- an act of terror now as well but do you do you feel like this has the signs.
Of of al-Qaeda of an international jihadist group I mean do you do you have any feeling based on what you've seen and heard so far.
No idea honestly -- I do not call they -- That the motive of -- of the way that these were utilized in other words we up to bombings.
Characteristic all of al-Qaeda.
I cannot argue that.
Many they are -- losses in the past have been much larger than -- I could not rule while.
A -- real lone wolf that is mad at as society or or whomever.
That could put these together -- that it's so.
Megan so very easy to go woman Internet.
And -- sure how to build a bomb and if you don't -- -- explosives.
Research on how to make your -- twenties that's why I mentioned.
Earlier own improvised explosives it's it is I'm soared to say virtually impossible in -- is -- a key word here.
To prevent anyone from improvising an explosive.
While Tom -- we hope that they have men with your expertise in women as well.
Looking into this we are grateful -- I know they -- and thank you so much for your expertise today.
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