Forensics Gone Wrong: When DNA Snares the Innocent (2016)

[throw0101d]

See also:

> The Phantom of Heilbronn, often alternatively referred to as the "Woman Without a Face", was a hypothesized unknown female serial killer whose existence was inferred from DNA evidence found at numerous crime scenes in Austria, France and Germany from 1993 to 2009. The six murders among these included that of police officer Michèle Kiesewetter, in Heilbronn, Germany on 25 April 2007.

> The only connection between the crimes was the presence of DNA from a single female, which had been recovered from 40 crime scenes, ranging from murders to burglaries. In late March 2009, investigators concluded that there was no "phantom criminal", and the DNA had already been present on the cotton swabs used for collecting DNA samples; it belonged to a woman who worked at the factory where they were made.[1]

* https://en.wikipedia.org/wiki/Phantom_of_Heilbronn

[bradyd]

There was also the case where a DNA test of a woman's children showed that they did not share any of her DNA. Social Services was threatening to take them away from her. When she had another child, the court ordered an officer to be present during the birth and collect DNA from both of them at that time. Even still the DNA "proved" she was not the mother. It was only after another similar case was discovered that they were able to determine that she was a chimera, basically that she was her own twin, and had two different DNA strands.

https://abcnews.go.com/Primetime/shes-twin/story?id=2315693

[LiquidSky]

Plot Twist: this woman WAS a prolific serial killer and, after realizing that she had left DNA behind at early crime scenes, got a job at the cotton swab factory to cover her tracks.

[asdfasdfjlk234]

Thank god an innocent person didn't get caught up in this. Imagine getting swabbed with bad technique and then the contamination coming back on you. In fact, that was exactly how they found out-- some man got swabbed and it came back with this woman's DNA.

[jansan]

Do people know about the Phantom of Heilbronn? For 15 years, police in Germany found DNA of one and the same person on about 40 different crime scenes. The crimes seemed to be completely unrelated, including murder, burglary, theft and even disputes between neighbors. This person was labeled "The Phantom" and all that was known aws that she was a female (XX chromosme type female). Everyone agreed that she must have been a true monster.

To keep it short, it was all a contamination of the swabs used by forensics. The DNA belonged to a worker in a factory where the swabs were produced. It took the police 15 years to find out. 15 years!

I sometimes wonder what would have happened if that woman had by accident become a suspect in a crime and her DNA run through the police's DNA database.

https://de.wikipedia.org/wiki/Heilbronner_Phantom

[dekhn]

Much of science involves the eliminate of false positives (this is a great example).

Throughout my career as scientist (I'm an ex-scientist now) and machine learning, I came to the conclusion that false positive rates must be kept extremely low for people to trust the system, because of the consequence of false positives.

[bborud]

DNA evidence is scary because we have decades of experiences and milestones saying that it isn't as simple and clear cut as we think it is, and still we treat it is hard, inarguable truth. Even though history teaches us we should know better.

It is one of those things that reminds me that most people with a science degree do not actually practice science.

[mrguyorama]

No, the scientists behind DNA testing absolutely understand the limitations.

The people who don't understand the limitations of science and possible errors in certain methods are clueless jurors and the cops who pay a random person $800 to sit on the stand, say they are "and expert" and claim there's a trillion to one odds that two people could have "the same" DNA, even though that isn't even remotely what was tested!

Courts allow basically anything as long as you can pay a guy to say they are an expert and parrot whatever you want. But somehow that's treated as if it's the fault of biologists and others who do DNA analysis?

Maybe our courts shouldn't be based on "Trust anything a cop says, period"

[rokkitmensch]

The American "justice" system is a poorly-disguised vengeance system in practice. One that doesn't particularly care about the correctness of its processes, so long as it can claim to have prosecuted and made miserable its victims.

The rot has metastasized into plain view with hokum like "911 call psychology", maliciously incompetent evidence handling, arson analysis, bullet analysis, civil forfeiture, and has even compromised previously honorable and integrity-backed professions with embarrassments like shaken baby syndrome.

Bring any of this up and you'll get excluded from jury duty at /voir dire/.

[Simplicitas]

The alternative being?...

[scorpio8902]

This is a really old story. Here are the updates: Tapp was exonerated in 2019: https://innocenceproject.org/cases/christopher-tapp/ Tapp receives $11.7 settlement from the City of Idaho Falls, ID, USA in 2022: https://www.cbsnews.com/news/christopher-tapp-wrongful-convi... Tapp dies in Las Vegas, USA in 2023: https://www.eastidahonews.com/2023/11/chris-tapp-idaho-falls...

[KMag]

$11.7 million, not $11.7.

[rysertio]

This is why DNA tests should always be done to exclude suspects, not to include them.

[dang]

Recent and related:

Hair sample that put a man in prison turned out to be dog hair - https://news.ycombinator.com/item?id=39110088 - Jan 2024 (41 comments)

[TrackerFF]

Very recently we had a cold-case here in Norway, old murder from the 90s (The murder of Birgitte Tengs), where the most recent suspect was first found guilty, but then acquitted on an appeal.

Back in the 90s police had found DNA on her leggings/pantyhose, which years later matched with him.

But they could not prove beyond a reasonable doubt that the DNA had gotten there through direct physical contact - as his DNA could have gotten there by them simply sharing some surface, like sitting on the same chair at a gas station.

[elevatedastalt]

The more I read about forensic "science", the more horrified I become. DNA is still a shining beacon of scientificity in that field. The other techniques that guided most crime scene investigation before DNA were a complete crapshoot. Blood-splatter analysis, fire investigation, psychological analysis of testimony, all these are basically only slightly above the "source: trust me bro" level.

It's horrifying.

[SpicyLemonZest]

A lot of what the article is saying makes sense, but I really wish the reporter had pushed a bit harder on Hampikian. He conducted a study to show that mixed DNA analysis can falsely exclude people, but are there similar studies that confirm the complex strategies he's exploring in the Tapp case can't falsely exclude people?

"Civil rights advocates object to [familial DNA] because it means that simply being related to an offender can make you a person of interest." If Hampikian knows that DNA can snare the innocent, shouldn't he be opposing any use of familial DNA rather than helping people use it in their appeals?

[giantg2]

It doesn't have to be 1-to-1. You can have different standards for offensive vs defensive use of the information. Showing the DNA matches some relative of a different family could be enough to generate reasonable doubt while still being too weak to generate probable cause to arrest or even search others.

Frankly, they had no probable cause to compell a DNA sample from that guys son. Probable cause is supposed to be that by a preponderance of the evidence that the person has committed the crime. That's clearly not the case as it could be anyone in that family, and with multiple suspects it's not 'more likely than not' that the individual is guilty. Instead the courts allow fishing trips.

[karmakaze]

> [...] he confessed after a series of lengthy interrogations that several experts have described as coercive. Police found plenty of male DNA at the scene, and it did not match Tapp's. But the prosecutor and jury believed his confession.

This story isn't even about DNA evidence.

[NoMoreNicksLeft]

Confessions need to be made inadmissible in court as evidence. All state legislatures have the power to make that so, as does Congress at the federal level. The judicial system could do it too, in theory, but never will.

Confessions could still be used by police as leads. While all "eyewitness testimony" is defective evidence, confessions are the most defective of all. Humans have weird psychology, but the psychology around confessions is the weirdest of all. It's why it's been exploited by the Catholic religion (and others). It causes strange (and not always unpleasant) emotions in those confessing, those hearing the confession, and even those confessing falsely. It causes them in those who confess because they were coerced, it causes them in those who choose to falsely confess without coercion. To those who are familiar with them, those pleasant feelings can become an irresistible temptation to falsely confess.

On top of that, it's been what, nearly 70 years since shows like the Twilight Zone introduced the idea to everyone that in unusual circumstances we might have done things we don't even remember. So when someone starts to break after long and even tortuous interrogations, they might themselves start to worry that they are guilty and their memories are faulty.

[jMyles]

It's true. People reliably confess to crimes they did not commit. It's just another dead canary in the cages of our justice system.

[Zigurd]

Evidence handling and testing should not be under the control of police, or even prosecution. Incentives need to be aligned toward justice, not convictions.

[picadores]

Full Process Surveilance is needed to make evidence admissable. If it aint filmed the whole way, it aint valid.

[arcbyte]

I think there's more work we can do to balance the power of individual defendants against the state, but the adversarial justice system is the most accurate and effective system for mediating public safety, punishment, and revenge ever developed in the history of the world.

[dylan604]

Well, if you don't think it should be under control of police or prosecution, who do you suggest needs to do it? The defense? A third party private contractor like Theranos? Who's going to be the ones validating whoever is decided can do the testing?

[TravisCooper]

Agreed. This is absolutely immoral. I don't know how we can trust that this evidence is useful in an "real" sense.

[konschubert]

This kind of tough talk sounds may sound good to you, but the end result will be that only thugs will dare to be DA.

There needs to be accountability, but this isn’t the way to do it

[marcinzm]

Then DAs, judges and police will make it their job to ensure no one is ever exonerated.

[bnralt]

We’ve had numerous cases here where prosecutors declined to press charges or gave a small amount of time as part of a sweetheart plea deal, and the criminal went on and killed someone. We’ve also had cases where the judge let a violent criminal out before trial and they killed someone. Should we make the judges and prosecutors culpable in those situations as well?

If you have strong penalties for the criminal justice system being too aggressive but none for the system being too lenient, your going to end up getting a lot of people killed by violent criminals who should be behind bars.

[sixothree]

Nobody has any skin in the game, police, prosecutors, judges. Not even their reputation or ability to get hired somewhere is affected by putting innocent people in jail.

[theGnuMe]

Yes but technically the jury are the ones who convicted.