Everything You Learned Watching Cop Shows is Wrong

And the FBI apparently wants you to stay ignorant. It makes their job easier. Why a High-Ranking FBI Attorney Is Pushing ‘Unbelievable’ Junk Science on Guns

First up is the current story, about firearms forensics.

For years, forensic firearms analysts have claimed the ability to examine the marks on a bullet found at a crime scene and match it to the gun that fired it—to the exclusion of all other guns. It can be powerfully persuasive to juries. But over the last decade or so, some scientists have cast doubt on the claim.

Forensic firearms analysis falls into a subcategory of forensics colloquially known as “pattern matching.” In these specialties, an analyst looks at a piece of evidence from a crime scene and compares it with a piece of evidence associated with a suspect.

That claim, that they can match a bullet to a gun went unchallenged for a long time. When you actually test them their accuracy falls to about 50 percent. Less than 50 percent.

Carriquiry points to another recent sensitivity study—funded by the FBI itself—in which the analysts’ success rate was just 48 percent. “A dispassionate observer would say that they would have made fewer mistakes if they had flipped a coin,” Carriquiry says. “Given that astonishingly low accuracy, it seems pure hubris to be recommending to examiners to ‘push back.’”

It has been a long time coming, but the Justice System (so called) doesn't want anything to upset the applecart of convictions, even if those convictions are based on a scam.

The first shot across the bow came in 2009, when the National Academy of Sciences published the first comprehensive, scientific review of forensics, which found that analysts routinely give testimony unsupported by scientific research, even though it’s often presented to and perceived by jurors as science.

In the wake of that study, the Obama administration created the National Commission on Forensic Sciences (NCFS), a large group of lawyers, scientists, judges, and statisticians tasked with identifying the shortcomings in forensic and prescribing solutions and best practices.

You can imagine how that went over. Click thru, there is a lot of detail on how the FBI, the DOJ, the National District Attorneys Association, and more want this to go away, so they can get back to convicting people. Don't clutter the issue with facts.

This report on firearm forensics is not the first time that the Justice System has pushed junk science to convict people. Fire science wasn't much of a science before the 1990s; before that it was wishful thinking. Scientific Advances in Arson Investigations Reveal Wrongful Convictions.

“A lot of bad science has been applied to arson investigation,” said fire expert John Lentini, who has provided testimony in over 40 arson cases since 2000. One of his recent cases involved a Massachusetts man, Victor Rosario, who was convicted of arson by Molotov cocktail even though no accelerant was found on any glass recovered at the crime scene.

Richard Roby, president and technical director of Combustion Science and Engineering, a fire protection engineering company based in Columbia, Maryland, has had similar experiences. “I shudder to think about how many wrongful convictions there are,” said Roby, who has testified for several defendants charged with arson. One, Michael Ledford, is serving a 50-year sentence for setting a fire that killed his son. According to Roby, however, Ledford could not have been present at the scene when the blaze was allegedly set. “It’s amazing to think how long it takes for basic science to be accepted,” he stated. “I lose sleep over this every week.”

Even fingerprints are not as infallible as the TV Shows would have you believe. Fingerprints Lack Scientific Basis for Legal Certainty.

"Everyone has distinctive fingerprints" is a statement that was accepted by the Justice System without any effort to see if it was actually correct. And if it could stand up to the limited 8-point analysis often used. But see, even asking the question means that they have to risk the answer being "No." They would rather have wrongful convictions than see any Justice in the world.

A new American Association for the Advancement of Science (AAAS) working group report on the quality of latent fingerprint analysis says that courtroom testimony and reports stating or even implying that fingerprints collected from a crime scene belong to a single person are indefensible and lack scientific foundation.

“Fingerprinting is one of the most heavily used forensic methods. Routinely, fingerprint analysts report and testify to ‘identification,’ that is, that the person who left the mark at the crime scene is the same person whose fingerprint is in the database, said Joseph B. (Jay) Kadane, Carnegie Mellon University’s Leonard J. Savage University Professor of Statistics and Social Sciences, Emeritus. “Our review of the scientific literature found that there is no scientific way to estimate the number of people in some community—a city, a state, the country, the world—who share the characteristics found, and hence no scientific basis for identification.”

None of this stops the Criminal Justice System from trying to WIN. It is what they value, because it is how they are rewarded. There are no rewards for Justice.

Tam, over at View From the Porch get's the hat tip for getting me started down this rabbit hole with It's not junk science, it's just junk, in which she has a number of pithy comments. I will leave you with this one.

Jurors have watched plenty of police procedurals on TV and think that projectile matching is some precise science when in fact going much beyond "Well, the octagonal polygonal rifling tells me this .45 caliber bullet was likely fired from a Glock" is educated guesswork.

Oh, and in case you were wondering, The CSI Effect is real. And don't get me started on Hollywood Hacking.