from Hacker News

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

by alphaomegacode on 1/24/24, 3:57 PM with 101 comments

  • by throw0101d on 1/24/24, 4:39 PM

    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

  • by jansan on 1/24/24, 4:40 PM

    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

  • by bborud on 1/24/24, 5:24 PM

    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.

  • by scorpio8902 on 1/24/24, 5:44 PM

    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...

  • by rysertio on 1/24/24, 5:38 PM

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

  • by dang on 1/24/24, 6:06 PM

    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)

  • by TrackerFF on 1/24/24, 6:19 PM

    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.

  • by elevatedastalt on 1/24/24, 6:49 PM

    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.

  • by SpicyLemonZest on 1/24/24, 4:36 PM

    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?

  • by karmakaze on 1/24/24, 4:46 PM

    > [...] 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.

  • by Zigurd on 1/24/24, 4:28 PM

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