> Detectable levels of DNA were also observed in air and dust samples from ultra-clean forensic laboratories which can potentially contaminate casework samples.
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.
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?
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.
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?
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.
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.
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.
> At 100% of the 130 examinations analyzed, seized drug analysis was the examination with the highest percentage of Type 2 errors. It was followed by pediatric physical abuse (83% of cases had forensic errors with 22% having Type 2 errors out of 60 cases analyzed), fire debris not including chemical analysis (78% of cases/38% Type 2 in 45 cases), bitemark comparison (77% of cases/73% Type 2 in 44), pediatric sexual abuse (72% of cases/34% Type 2 in 64), serology (68% of cases/26% Type 2 in 204), shoe/foot impressions (66% of cases/41% Type 2 in 32), DNA (64% of cases/14% Type 2 in 64), hair comparison (59% of cases/20% Type 2 in 143), and blood spatter (58% of cases/27% Type 2 in 33).
Also this sample comes from cases where people were exonerated, which could cluster around poor quality police work in general. And is US-based where policing is all kinds of messed up.
A few years ago i picked up the old (but famous) cases of Brad Cooper and Casey Anthony as they have tons of available digital forensics evidence.
I double-checked the forensics work and found several mistakes in processes, assumptions and technical conclusions. I sent off my findings to people associated with Project Innocence - not because I found anything that proved Cooper or Anthony's innocence, quite the opposite. Instead, I wanted to let them know that forensics experts can make mistakes.
It is interesting that scientific work have fault-finding processes like peer-reviews, but forensics investigations in court cases does not.
> going to a seedy part of town, picking up a dropped cigarette butt, and leaving it at the crime scene
I've sometimes conjectured collecting hair from barbershops and making a dusting bag that steadily fluffs out hairs to dirty up a crime scene. Maybe get some saliva from grocery store sample spoons.
> 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
Framing someone else is not a perfect crime. A perfect crime finds no criminal, accused or convicted.
When we're talking about quality of evidence, saying "in reality" is skipping to your conclusion. Are smart careful people rare among known criminals? Well, yes. What would you expect to see? https://www.econlib.org/archives/2015/02/the_wittgenstei.htm...
"Mr Butler has a rare skin condition, which means he sheds flakes of skin, leaving behind much larger traces of DNA than the average person. He worked as a taxi driver, and so it was possible for his DNA to be transferred from his taxi via money or another person, onto the murder victim."
Because people believe it, and courts have accepted as fact that DNA evidence is infallible. Certainly there have been cases where DNA has been successfully challenged, but those are very rare. In the overwhelming number of cases where DNA evidence is present, it is a self-fulfilling prophecy for juries and judges.
If there is DNA evidence that is almost a guilty verdict. It should be more closely scrutinized but not everyone is rich enough to afford a real defense.
That seems an especially good reason to distrust DNA evidence using the technique from this paper. It relies on such a small amount of DNA, in dust, that if someone opened a window and a stranger walked by, the interior of a room might be contaminated with the strangers DNA. Also people are mobile, their clothing will pick up DNA dust from one location and shed it in another location. There may already be DNA dust from a million people in any one location. Even if you suck the DNA directly out of the air, you don't know where that air has previously been.
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
Do you think this would become doable by private citizens in the near future for a reasonable amount of money? I've been curious about how far upstream the sculpins are in our local streams. I've seen some in pretty small streams but looking for them typically involves standing still in very cold water for long enough to see them move.
They send you usually a syringe with some filter paper in it, you push water through the filter paper, send the paper back, and they sequence the DNA stuck in the paper and send you a report (and add the sightings to their database).
I’m not sure! Because the water would move the dna relatively quickly it could be hard to get good results at the higher ends of their range. And I’m not sure about costs, but I’ll look into it.
One strategy that might work, though you’d need to take care and get permission: create a barrier to downstream so sculpins can’t come upstream, and place a trap above the barrier and see if any enter the trap after a few hours. That should tell you if they’re occupying that part of the stream. Just sticks with a mesh net placed as a barrier should be sufficient to prevent any downstream occupants from coming up and entering the trap.
Another would be to place a camera in the water and review the footage. I use this approach with an iPhone 15 Pro (I just stick it straight in the stream) and I get excellent results. There are always really cool animals popping up. Here’s an example: https://youtu.be/N9PLra7amfs?si=kZ01cFZ8upKLxNPb
This was in a very tiny puddle off the side of a creek in summer. At a glance it appeared empty, but after putting the camera in and walking away for 10 minutes or so, all kinds of creatures like this sticklebacks came out of the detritus.
Thanks. I guess I was thinking about looking to see if there is dna from upstream passing by. At some point I'd guess it is hard to tell if there are fish upstream but I'm not sure how to think about what factors are important. On the other hand just looking at streams isn't the worst thing to do.
I don't think my own curiosity is a good enough reason to build a trap or barrier. But a camera is a good idea. I actually just picked up some parts from blue robotics to put together a setup for one or more cameras using some stuff I have laying around.
Cool sticklebacks! One of the places I stumbled on Sculpins was in the Taylor River on Vancouver island. I saw something moving and nearly froze myself staying in until I found several of them.
Nice, I was very close to that area (maybe 50km over the woods and mountains to the east). There were tons of sculpins in that river, too. Such a beautiful area.
I've never seen blue robotics before. I almost wish I hadn't, haha. This is going to soak up some time.
Their low light USB camera looks awesome for stream monitoring. You could probably even get decent footage in the shady areas (where I find a lot of fish prefer to be). Maybe under some rocks on an overcast day with lots of diffused light? Could be awesome!
Its peak draw is only 220mA so you could actually record a ton of footage on a raspberry pi 5 without a massive power source (10,000mAh should get you somewhere around 2.5 hours, I think?)
This article... keeps repeating phrases about criminals, authorities, safe-houses, solving crimes. Feels off. I was expecting this to focus on the lab techniques, feasibility, technical details. It jumps straight from forensic application details to results without the in-between. I think the in-between is the interesting part.
It's as if they took the token sentence that goes in an abstract about potential applications, and turned it into the meat of the article.
It sounds like they are using standard extraction kits, them analyzing with RT-PCR.
I wouldn't be surprised that some some agencies *cough*Mosad*cough* are gathering DNA of leaders of all countries, and analyzing them, and potentially building bioweapons to target them. It looks like all you need to do is to get the HEPA filter from the room where the target was .
This sounds very expensive, of uncertain efficacy, and if you use an engineered organism, it will likely be detected if you use modified DNA.
I accept an agency like Mosad or the CIA would attempt it though. CIA tried so many crazy schemes to try to kill or embarrass Castro and failed every time. Mosad loves balls to the walls evil schemes too, like the pagers. It would be one of those situations where they leave a stupid trace and everyone knows it's them and they are untouchable so they don't care and even enjoy the attention.
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...
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.
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.
> 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?
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.
> unalived himself
In English the phrase is “killed himself”.
TIL that the kids actually use it [1], and it's in dictionaries [2] etc so arguably it's actually English.
[1]: https://medium.com/new-writers-welcome/unalive-the-birth-of-...
[2]: https://www.dictionary.com/browse/unalive
Edit: typo.
Feel free to use your choice of synonym when you are writing something.
You can say he killed himself it’s not kitkots
Tiktots?
Interesting. Link or something?
I provided some more details and a link here: https://news.ycombinator.com/item?id=43396911
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?
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.
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-...
What if the murderer works in the lab?
The Phantom of Heilbronn!
https://en.wikipedia.org/wiki/Phantom_of_Heilbronn
That was interesting story, the ending in hindsight seems obvious. Thank you for sharing.
[dead]
The defense attorneys of criminal criminal forensics lab technicians at least.
Phantom of Heilbronn strikes again: https://en.wikipedia.org/wiki/Phantom_of_Heilbronn
Dexter Morgan wins again.
https://www.imdb.com/title/tt0119177/ was conservative. Great movie though.
I feel like this is one of those prescient movies like Pleasantville and Idiocracy we should force voters to watch again before voting.
[dead]
Does seem strange in retrospect that if looking for 'invalids' is so paramount, just install Hoover air curtains everywhere.
So glad someone mentioned that. A great movie I still enjoy today!
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.
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.
>so DNA and fingerprints work just fine almost all the time.
except for all of those innocent folks that have had their lives ruined by that 'almost all the time' caveat, it's great!
here's a report[0] that says something like 80% + of criminal forensic work has major mistakes within it.
[0]: https://www.criminallegalnews.org/news/2024/may/15/report-fi...
Quoting from that:
> At 100% of the 130 examinations analyzed, seized drug analysis was the examination with the highest percentage of Type 2 errors. It was followed by pediatric physical abuse (83% of cases had forensic errors with 22% having Type 2 errors out of 60 cases analyzed), fire debris not including chemical analysis (78% of cases/38% Type 2 in 45 cases), bitemark comparison (77% of cases/73% Type 2 in 44), pediatric sexual abuse (72% of cases/34% Type 2 in 64), serology (68% of cases/26% Type 2 in 204), shoe/foot impressions (66% of cases/41% Type 2 in 32), DNA (64% of cases/14% Type 2 in 64), hair comparison (59% of cases/20% Type 2 in 143), and blood spatter (58% of cases/27% Type 2 in 33).
Also this sample comes from cases where people were exonerated, which could cluster around poor quality police work in general. And is US-based where policing is all kinds of messed up.
A few years ago i picked up the old (but famous) cases of Brad Cooper and Casey Anthony as they have tons of available digital forensics evidence.
I double-checked the forensics work and found several mistakes in processes, assumptions and technical conclusions. I sent off my findings to people associated with Project Innocence - not because I found anything that proved Cooper or Anthony's innocence, quite the opposite. Instead, I wanted to let them know that forensics experts can make mistakes.
It is interesting that scientific work have fault-finding processes like peer-reviews, but forensics investigations in court cases does not.
> going to a seedy part of town, picking up a dropped cigarette butt, and leaving it at the crime scene
I've sometimes conjectured collecting hair from barbershops and making a dusting bag that steadily fluffs out hairs to dirty up a crime scene. Maybe get some saliva from grocery store sample spoons.
> 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
Framing someone else is not a perfect crime. A perfect crime finds no criminal, accused or convicted.
Creating reasonable doubt as a backup plan in case your perfect caper isn't as perfect as you believe is just good practice.
Rule 43(a) in the criminal procedures handbook IIRC.
When we're talking about quality of evidence, saying "in reality" is skipping to your conclusion. Are smart careful people rare among known criminals? Well, yes. What would you expect to see? https://www.econlib.org/archives/2015/02/the_wittgenstei.htm...
Reminds me of the case of David Butler.
"Mr Butler has a rare skin condition, which means he sheds flakes of skin, leaving behind much larger traces of DNA than the average person. He worked as a taxi driver, and so it was possible for his DNA to be transferred from his taxi via money or another person, onto the murder victim."
https://www.bbc.com/news/science-environment-19412819
Because people believe it, and courts have accepted as fact that DNA evidence is infallible. Certainly there have been cases where DNA has been successfully challenged, but those are very rare. In the overwhelming number of cases where DNA evidence is present, it is a self-fulfilling prophecy for juries and judges.
If there is DNA evidence that is almost a guilty verdict. It should be more closely scrutinized but not everyone is rich enough to afford a real defense.
That seems an especially good reason to distrust DNA evidence using the technique from this paper. It relies on such a small amount of DNA, in dust, that if someone opened a window and a stranger walked by, the interior of a room might be contaminated with the strangers DNA. Also people are mobile, their clothing will pick up DNA dust from one location and shed it in another location. There may already be DNA dust from a million people in any one location. Even if you suck the DNA directly out of the air, you don't know where that air has previously been.
Well, that’s going to make it harder to hide from the hunter-killer bots
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
Jeff Bezos is probably already throwing millions of dollars at this in case it'll help him punish people for having a toilet break.
Fart detector
Do you think this would become doable by private citizens in the near future for a reasonable amount of money? I've been curious about how far upstream the sculpins are in our local streams. I've seen some in pretty small streams but looking for them typically involves standing still in very cold water for long enough to see them move.
There are some direct-to-consumer companies popping up that do this for you for <$300 per sample. New Zealand has Wilderlab, for example, https://www.wilderlab.co.nz/, the UK has Nature Metrics https://www.naturemetrics.com/
They send you usually a syringe with some filter paper in it, you push water through the filter paper, send the paper back, and they sequence the DNA stuck in the paper and send you a report (and add the sightings to their database).
I’m not sure! Because the water would move the dna relatively quickly it could be hard to get good results at the higher ends of their range. And I’m not sure about costs, but I’ll look into it.
One strategy that might work, though you’d need to take care and get permission: create a barrier to downstream so sculpins can’t come upstream, and place a trap above the barrier and see if any enter the trap after a few hours. That should tell you if they’re occupying that part of the stream. Just sticks with a mesh net placed as a barrier should be sufficient to prevent any downstream occupants from coming up and entering the trap.
Another would be to place a camera in the water and review the footage. I use this approach with an iPhone 15 Pro (I just stick it straight in the stream) and I get excellent results. There are always really cool animals popping up. Here’s an example: https://youtu.be/N9PLra7amfs?si=kZ01cFZ8upKLxNPb
This was in a very tiny puddle off the side of a creek in summer. At a glance it appeared empty, but after putting the camera in and walking away for 10 minutes or so, all kinds of creatures like this sticklebacks came out of the detritus.
Thanks. I guess I was thinking about looking to see if there is dna from upstream passing by. At some point I'd guess it is hard to tell if there are fish upstream but I'm not sure how to think about what factors are important. On the other hand just looking at streams isn't the worst thing to do.
I don't think my own curiosity is a good enough reason to build a trap or barrier. But a camera is a good idea. I actually just picked up some parts from blue robotics to put together a setup for one or more cameras using some stuff I have laying around.
Cool sticklebacks! One of the places I stumbled on Sculpins was in the Taylor River on Vancouver island. I saw something moving and nearly froze myself staying in until I found several of them.
Nice, I was very close to that area (maybe 50km over the woods and mountains to the east). There were tons of sculpins in that river, too. Such a beautiful area.
I've never seen blue robotics before. I almost wish I hadn't, haha. This is going to soak up some time.
Their low light USB camera looks awesome for stream monitoring. You could probably even get decent footage in the shady areas (where I find a lot of fish prefer to be). Maybe under some rocks on an overcast day with lots of diffused light? Could be awesome!
Its peak draw is only 220mA so you could actually record a ton of footage on a raspberry pi 5 without a massive power source (10,000mAh should get you somewhere around 2.5 hours, I think?)
Yeah, eDNA is exactly what I thought of when I saw this.
More like who is sick a lot (sneezing and distributing dna on multiple surfaces in the blast radius)
This article... keeps repeating phrases about criminals, authorities, safe-houses, solving crimes. Feels off. I was expecting this to focus on the lab techniques, feasibility, technical details. It jumps straight from forensic application details to results without the in-between. I think the in-between is the interesting part.
It's as if they took the token sentence that goes in an abstract about potential applications, and turned it into the meat of the article.
It sounds like they are using standard extraction kits, them analyzing with RT-PCR.
Makes me wonder if dogs can smell your DNA.
So, DNA shedding basically?
Anyone remember the movie Gattaca?
If you know my mother in law, you don't need a DNA tester to know she's been in the restroom.
[dead]
I wouldn't be surprised that some some agencies *cough*Mosad*cough* are gathering DNA of leaders of all countries, and analyzing them, and potentially building bioweapons to target them. It looks like all you need to do is to get the HEPA filter from the room where the target was .
This sounds very expensive, of uncertain efficacy, and if you use an engineered organism, it will likely be detected if you use modified DNA.
I accept an agency like Mosad or the CIA would attempt it though. CIA tried so many crazy schemes to try to kill or embarrass Castro and failed every time. Mosad loves balls to the walls evil schemes too, like the pagers. It would be one of those situations where they leave a stupid trace and everyone knows it's them and they are untouchable so they don't care and even enjoy the attention.