Post-Explosion DNA Tracing

[Bander]

<a href="http://www.newscientist.com/news/news.jsp?id=ns99993426" target="_blank">New Scientist: Bomb Fragments Hold DNA Clues</a>

Summary: It is apparently possible to create a genetic fingerprint from post-explosion debris that could conclusively prove a suspect, from whom they have a DNA sample, had handled the device prior to detonation. The procedure seems to work best in low-order detonations, and only a certain percentage of the time (as would be expected).

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica">Kelly Esslinger at Michigan State University in East Lansing and Heather Spillane at the Michigan State Police Crime Laboratory in Northville set up an experiment to see whether DNA could be detected on exploded bomb fragments and matched to a suspect. They found traces of DNA on one in five bombs exploded under controlled conditions.

Ten subjects were asked to handle one metal and one PVC pipe bomb each. They were told to touch each component (the pipe, caps and fuse) for about 10 seconds. After storing the bombs for a month in sterile bags, the researchers exploded each in shallow holes covered with earth and a large rock. They collected fragments from inside the hole to avoid contamination from elsewhere.

The researchers then applied a sensitive method of DNA fingerprinting which traces short tandem repeats (STRs). These short regions of DNA contain repeated elements of two to seven letters. Different people have different numbers of repeats at different sites, so the combination of enough sites constitutes a unique DNA fingerprint. Esslinger attempted to amplify 13 STRs from DNA on the bomb fragments.</font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">The genetic camouflage techniques discussed in this <a href="http://www.roguesci.org/cgi-bin/ewforum/ultimatebb.cgi?ubb=get_topic;f=13;t=000053#000000" target="_blank">thread</a> would seem prudent from now on if one is going to 'dream' about anything that would draw attention. As well as careful preperation of the device while wearing gloves and other protective clothing, naturally.

[spydamonkee]

Hmmm interesting, I've often wondered what evidence would be left after a blast but personally I dont think it will be working too well with High Explosive devices as the heat generated should destroy any DNA left on the device.

I suspect they were using a LE to test their devices thus the metal & plastic pipebombs, well hopefully they will perfect this method and will catch all the stupid lil anarchist cookbook fans that run around with pipeboms & the likes

[Al Koholic]

Thats why you can't even touch the shit these days. In fact its better if it's not touched even by things that have been touced....or breathed on, or been around without a cleansuit on and prepared in a clean room. Some of the investigative stuff is getting so sensitive these days that they can tell the emotional state of someone who looked at the PVC pipe 4 months ago. Hehehe wouldn't that be the day...but I suppose if it ever got that hardkor we'd have more problems on our hands. Anyway, this being the case, you'd want to use an object that had been touched by TONS of people besides you prior to the construction. If anything it would cause the waste of money and time on the investigative teams behalf.

[megalomania]

Not only could this technique be used to identify a bomber, but it could also be used to identify the clerk who sold it to the bomber, or the laborer who handeled it. If they found the clerk, say, they could narrow down the area of the bomber.

This technique dosn't sound as if it would be all that accurate considering what little DNA there would be to begin with, let alone after detonation. It would be more useful in tracking down kewl bombers when their AP pipe bomb goes poof, not massive explosions like Oklahoma city. That means they are targeting the little guy, not big terrorists.

[shooter3]

This still will not be very conveniante. You will need a large database of suspects, like the total population of the earth. Start looking for the mark of the beast(implanted chip with your dna code in it).

[Bander]

Thank *diety* for google, the <a href="http://mafs.net/pdf/esslingerpresentation.pdf" target="_blank">actual presentation</a> on the technique in pdf form. IMR TM powder SR 4756 by DuPont was used, and 'category 3' explosions seem to negate the procedure. Any true HE would fit into this definition based on the pictures of container fragments describing each class included in the document.

Re: Database Profile Matching Comments

It is not likely they could use the DNA fragments specified in the article to identify someone without having them as a suspect beforehand since the process isn't quite the same as traditional gel electrophoresis DNA analysis; but a more robust, less accurate process altogether that uses different strings/patterns. To do a widespread search through a DNA database seems quite unlikely/impossible since the short tandem repeats would have to be individually extracted, and I don't think that is even possible, from the electrophoresis patterns(?) stored on file. Also, there is a chance that the enzymes used in the traditional process would cut STRs up, making matching impossible. In summary, I do not think anyone has to worry about having their DNA from a post-detonation scene being matched with what may or may not be on file.

My understanding of both these (DNA matching) processes is limited though, and there may be errors in my reasoning. So don't be too confident. :p

But you do have to worry if you are already a suspect and there was incomplete detonation.

[NightStalker]

It's getting to be that you'll have to use a glovebox to build your devices in lest some lab geek find some miniscule trace of your body on it and plug your DNA into The Beast , which will promptly spit out your address for the JBT's to gaffle you up with.

Obviously any DNA on the inside of the device, in direct contact with the explosive, will be destroyed by the heat. Destruction of that on the outside, though, would be dependant on the type of explosive, size of the charge, etc.

True, those most at risk from this would be the little shits with their fearsome COB's full of AP, not the raghead building a 2,000 pound truckbomb.

The prudent terr would include a large incendiary device with his device so that, in case of failure to detonate, it would still burn up, destroying any DNA trace. Perhaps coating all surfaces with a pyrotechnic coating, like NBK described once, would help ensure destruction after explosion by burning off after ignition from the explosion?

Using very hot explosives with high Al/Mg/Zr metal loading would really roast it. Thermobaric/FAE would seem impervious to DNA testing due to their very nature. Same for incendiaries.

[chemwarrior]

Now wouldnt it be funny if someone real high and might :rolleyes: , (president, vice president, senators, etc.) were to have their prints found all over a 'terrorist device'?

[cutefix]

It would be funny if these VIPs were blasted to pieces trying to frantically defuse an explosive device(supposing they have prior military training before the got the hallowed position) they found planted in their premises by a professional assasin and there is nobody around to help them.