Extracting DNA from the air – DNA evidence of human occupancy in indoor premises
27 comments
·March 15, 2025treetalker
From the abstract:
> Detectable levels of DNA were also observed in air and dust samples from ultra-clean forensic laboratories which can potentially contaminate casework samples.
Great news for criminal defense attorneys.
mrtksn
It cuts both ways, there was this high profile case of the son of a very rich and powerful family brutally murdering his working class girlfriend in his family mansion with some family present, motives still unknown.
In the autopsy they discovered sperm from a 3rd person on her body, tried to claim that it was an infidelity case(you get different sentece depending on your motives and circumstances) but later it was revealed that this was just a contamination during the autopsy.
So, the more forensic options the better but likely longer and more expensive trials. All lawyers win.
paulluuk
> just a contamination during the autopsy.
How does sperm end up on her body during the autopsy? Are we talking necrophilia or are there multiple murdered bodies laying next to each other and the tools are re-used or something?
mrtksn
IRRC The official explanation is that there were a few autopsies going on at the same time in that facility and it came from the body next to hers. The public opinion was that they bribed the technician to contaminate her body.
The whole case is a huge mess with attempts of cover ups, months long manhunts and all kinds of conspiracy theories. The killer was sentenced to 24 years of prison but unalived himself in prison and there're still conspiracy theories saying that he actually escaped to China because he was studying Chinese in prison prior that. This happened more than 10 years ago and last year they opened his grave to check the remains and again it was confirmed that that's him. Yet, this is still not enough to end the public discussion and conspiracy theories.
Anyway, if anyone is curious this is the case in question: https://en.wikipedia.org/wiki/Murder_of_Münevver_Karabulut
Unfortunately, the juicy literature around that is mostly in Turkish.
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moontear
How would that argument go? As far as I understand it, the DNA of the occupants of said lab may be found. That would mean that the criminal samples may also contain DNA of the lab occupants/scientists. Isn’t that the case currently as well and those DNA parts would be omitted?
greenpresident
That would ideal, yet we still got things like this:
https://en.wikipedia.org/wiki/Phantom_of_Heilbronn
Woman at a cotton swab factory was identified after being considered a serial killer.
yzydserd
It’s possibly not the GP’s point, but in general the more DNA that is available the better from a defense perspective. Many wrongful convictions involve a lack of physical evidence. Recent advances like “touch dna” and “m-vac” have led to new DNA evidence used in actual innocence decisions. Too often, a jury convicts a likely suspect on weak circumstantial evidence. Just as with Touch DNA, Air DNA will create new problems with avoiding contamination.
The path toward Air DNA has been known for years [0]. Wouldn’t be surprised to learn crime scene investigators have been sampling and storing air in high profile cases ready for the tech to catch up.
[0] https://www.science.org/content/article/dna-pulled-thin-air-...
thfuran
The defense attorneys of criminal criminal forensics lab technicians at least.
looofooo0
Phantom of Heilbronn strikes again: https://en.wikipedia.org/wiki/Phantom_of_Heilbronn
Hupriene
Dexter Morgan wins again.
dc396
https://www.imdb.com/title/tt0119177/ was conservative. Great movie though.
bilekas
So glad someone mentioned that. A great movie I still enjoy today!
steve_adams_86
At work we do this with DNA floating around in the ocean (have to track down all those nasty invasive crabs) but I wouldn’t have guessed we could do this with the air around us as well. That’s so cool.
Maybe we should spin up an air-based version for the office to keep track of who’s in coming to work the most
DecentShoes
Jeff Bezos is probably already throwing millions of dollars at this in case it'll help him punish people for having a toilet break.
Lanolderen
Fart detector
MostlyStable
Yeah, eDNA is exactly what I thought of when I saw this.
faangguyindia
More like who is sick a lot (sneezing and distributing dna on multiple surfaces in the blast radius)
h1fra
I have always wondered why DNA is an accepted evidence. It's so easy to contaminate a crime scene or bring someone else hair, skin cells, etc by mistake.
rwmj
In theory, you could do a "perfect crime" by going to a seedy part of town, picking up a dropped cigarette butt, and leaving it at the crime scene, framing someone else.
In reality, criminals are angry, frightened, in a rush, high or stupid, and they make the most elementary mistakes, so DNA and fingerprints work just fine almost all the time. In like 99% of cases there's not much doubt about who did it, the main thing is to have a watertight case against them when they deny it.
This is a slightly older paper, note that air environmental DNA now has progressed a lot, especially for species mapping.
Here's a cool recent paper showing you can extract DNA of local species from spider webs, by sequencing DNA stuck to spider webs from next to a zoo https://www.sciencedirect.com/science/article/pii/S258900422...