pbray

In the latest news from the FBI crime labs, an admission that they've been overstating the likelihood of DNA matches, a problem that dates back to at least 1999.

This is part of a series of reviews that have revealed systemic problems with forensic evidence provided by the FBI. Back in 2012 they revealed similar issues with hair & fiber evidence, these dating back to the 1980s. Not to mention the earlier well-publicized problems with gunfire residue evidence and fingerprint analysis.

Back in 2009 the National Academy of Sciences went before Congress with a scathing indictment of the state of forensic science at all levels of law enforcement in the US, pointing out that the lack of standards and scientific rigor meant that junk science was routinely being presented, unchallenged, at criminal trials. In an optimistic view, one could say the latest report from the FBI shows that they've committed themselves to reform, and are being open about the past.

Or you could say that they are just as likely to learn from this as they learned from the FBI lab scandals in the 1990s...which is to say, not at all. Bad FBI science.

Interesting article on the BBC website about upcoming changes to the FBI's DNA database.

One thing most people don't realize is that when DNA information is stored or analyzed for comparison purposes, they don't use the entire sequence. Instead they use selected markers, basically a small subset of the total DNA. Which, of course, leads to two potential problems. First, if two databases use different markers, you can't easily compare data between the two systems, a potential problem when trying to share information across jurisdictions.

The second problem is what they refer to as chance matches. The situation where a DNA match is declared based on the subset of DNA examined, when, in fact, a broader comparison would reveal that the DNA is not identical. This is the possibility that troubles forensic scientists, who are still trying to work out how much data needs to be stored in a profile in order to rule out the possibility of chance matches.

And for those who assume well this is the FBI, of course they wouldn't declare themselves certain of a match unless they were, let's not forget Brandon Mayfield. He's the Seattle lawyer whose fingerprints the FBI mistakenly matched to the terrorist bombing in Spain, an analysis which was vigorously defended by the FBI even after Spanish law enforcement declared it to be in error. Eventually Mayfield received a rare public apology from the FBI, but if this had been a strictly domestic case, rather than a high profile case that crossed borders, one wonders if the mistake would ever been caught.

The media has once again discovered that real life isn't the same as TV, as USA Today breathlessly reports that CSI isn't an accurate representation of police forensics.

The article was inspired by the report from the National Academy of Sciences to Congress on the state of forensics and use of evidence in this country. The press release from NAS and audio of their briefing can be found here or you can listen to the story on NPR. Much of what is in the report reflects concerns that have been raised before, but this is a sweeping indictment of the overall system.

Left foot washes up on beach near Vancouver. Note that this is the fifth foot found in this area since last August, but all of the previous finds have been right feet.

It's the very bizarreness of the story that captures the imagination. An entire body washing up along shore is one thing, but just feet?

Edited on 6/18 to add: and they've just found a sixth foot. A right one.

Edited on 6/19 to add: the sixth foot was a hoax--skeletonized animal paw wrapped in seaweed and stuffed in shoe. The recent news coverage has apparently brought out the crazies.

Not dead yet, though today is the 10th consecutive work day, which is one of the reasons I've been posting infrequently. And speaking of dead, yesterday I finished reading the first of my birthday loot: NEVER SUCK ON A DEAD MAN'S HAND: Curious Adventures of a CSI by Dana Kollmann.

Overall I liked the book, but its strengths are also its weaknesses. Reading this book feels like taking Dana out for coffee (or a few drinks) and listening as she tells tales from her days as a CSI. It's a fascinating insight into the non-glamorous parts of the job, and what doesn't get shown on TV. But there's not a lot of structure to the book--stories wander, break off at odd points, there's entirely too much detail in some spots and too little in few. Every now and then she hints at a story but then wanders off in another direction, leaving the reader unfulfilled. If I were listening to her in person, I could prompt her to go back to fill in the missing blanks, but as it is, I kept reading and only when I reached the end did I figure out that she wasn't ever going to finish that story.

And as a warning, the gross out factor is high. Very high. As in do not attempt to eat or drink during or after reading certain sections, and be prepared to gag. I'd thought the full-color photographs of decomposing bodies from my Criminal Investigations textbook would have inured me to such things, but if you have a vivid imagination, the word pictures that Dana paints are even more gag-inducing.

Overall recommended, if you're a CSI junkie, or simply enjoy reading about someone who thinks burying roadkill in the front yard is an acceptable hobby.

Received an A in the Criminal Investigations course I just finished up. I'm ridiculously pleased.