Wednesday, April 22, 2015

If the FBI says "science" you should probably acquit

I'm pro law enforcement.  I support our police in their very tough job.  Even so, there have been some disturbing trends in recent years.  The militarization of our police has led to a police vs. civilians mentality that can be dangerous and even lead to out of control officers.  There are some great programs like community-oriented policing that help to combat that and remind officers and the average citizen that we're partners in making our neighborhoods safer.

Also, despite my pro law enforcement stance, I know you should never, ever talk to the police if you're suspected of anything.  Their job is to support the prosecution and put bad guys in jail.  For more, check out the videos linked here.

That brings me to some shockingly bad police work and going too far to get a conviction.  Most people trust the FBI.  If they are involved, we feel like they'll get the job done and the bad guy will go to prison.  Unfortunately, so do a lot of innocents.

FBI admits flaws in hair analysis over decades

From that article:
Of 28 examiners with the FBI Laboratory’s microscopic hair comparison unit, 26 overstated forensic matches in ways that favored prosecutors in more than 95 percent of the 268 trials reviewed so far, according to the National Association of Criminal Defense Lawyers (NACDL) and the Innocence Project, which are assisting the government with the country’s largest post-conviction review of questioned forensic evidence.

The cases include those of 32 defendants sentenced to death. Of those, 14 have been executed or died in prison, the groups said under an agreement with the government to release results after the review of the first 200 convictions.
The Constitution, especially the Fourth and Fifth amendments, is designed to protect the innocent.   Penned by people who had seen friends go to prison at the whim of the crown, the intent was to prevent the government ever having the power to abuse its right to use force or imprison.  This should never have happened.

That's not the scariest part.  They've done it before.  Hearing about this issue triggered a memory of one from a decade ago.  This is again the FBI misrepresenting data to get false convictions.

Science Casts Doubt on FBI's Bullet Evidence

This article explains that the FBI for years has used trace impurities in lead to match crime scene rounds to rounds in possession of suspects.  The theory is that each batch of ammunition varies enough to determine if bullets used in a crime match a box in the suspect's possession.  If it matches, the rounds came from the suspect and the suspect is guilty.  It's often used when there's little or no other evidence.  It's so convincing California nearly passed a law based on the idea.

And it's junk science.
A Times examination of technical studies and trial transcripts -- and interviews with former FBI technicians, independent scientists and legal scholars -- suggests that the bureau's use of evidence derived from the lead in bullets may be based on faulty assumptions that greatly overstate the importance of matches.

The FBI likens its lead technique to fingerprint analysis. Bullets found at crime scenes are tested for minute amounts of arsenic, tin, silver and other contaminants or additives. Those findings are compared with results of similar analysis of bullets found in the possession of suspects. FBI examiners have claimed in court to be able to link one bullet to others from the same production run -- even from the same box.

The technique has proved especially important in cases in which prosecutors have little or no direct evidence, such as fingerprints or an eyewitness identification.
There is no dispute that trace elements of chemicals can be precisely measured in bullets. The controversy centers on how the FBI interprets the data.

For years, FBI laboratory examiners operated on the assumption that each batch of bullet lead was unique. So if the same trace elements were found in the same concentrations in two bullets, the reasoning went, those bullets must have been made at the same time and in the same place.

Premises Questioned

Recent scientific studies have concluded that this premise is wrong. Studying blocks of lead used in the manufacture of bullets, researchers have found the same chemical makeup in batches made at different times. They also have reported that the concentration of trace elements can vary significantly in the same casting of lead.

If the skeptics are right, the matches found by FBI lab technicians are meaningless.
Woops.  The trace impurities don't just differ from batch to batch but from round to round.   So a match could have come from anyone's box of ammunition, and two rounds fired from the same box may differ significantly from one another.

In both of these stories, it seems like the FBI was aware of the flaws and went ahead in overstating the significance of the evidence anyway.

The FBI won't want me on any juries.  If they say, "science" or "forensics" I'll be forced to acquit if there's no other strong evidence in the case.  I won't be party to a 95% error rate.  Understand that if the FBI techs said someone was guilty based on microscopic hair comparison, 95% of the time that wasn't true.  That's huge.  You could essentially acquit anyone they claimed was guilty if microscopic hair evidence was the basis for their argument.

Fortunately for the FBI, most people won't hear or remember these stories.  Don't be most people.  I appreciate law enforcement, but can't support putting innocent people in jail because of overzealous misrepresentation of evidence.

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