Fingerprints Recoverable From Cleaned Metal 178
dstates points out a recent article from guardian.co.uk which discusses a new method by which to recover fingerprints from metal. The method relies on corrosion caused by sweat and other biological residues on the metal's surface. Quoting:
"The patterns of corrosion remain even after the surface has been cleaned, heated to 600C or even painted over. This means that traces of fingerprints stay on the metal long after the residue from a person's finger has gone. The chemical basis of the change is not yet clear, but [Dr. John Bond] believes it is corrosion by chloride ions from the salt in sweat. These produce lines of corrosion along the ridges of the fingerprint residue. When the metal is heated, for example in a bomb blast or when a gun is fired, the chemical reaction actually speeds up and makes the corrosion more pronounced."
Plastic weapons (Score:2, Insightful)
This will open up the renaissance of plastic weapons.
Re:Plastic weapons (Score:5, Insightful)
Or salted lemon wet naps (Score:4, Insightful)
I mean come on - not too hard to get around, but still it's interesting.
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it would seem to be only circumstantial evidence though.. nearly every person who fired the gun would leave a "permanent" fingerprint. That would reduce the utility of this. I suppose what they're after is damaged metals though. Like from bombs or car crashes during persuit to be able to figure out who the guy working on the metal was when he's cinders.
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Or perhaps it will cause criminals to start taking better care of their guns. A well oiled gun won't have this problem.
Or use stainless steel guns.
I guess the most impact could be if they could check guns from unsolved crimes from the last 50 years, if no dumbwit copa handled them without gloves that is.
Damnit! (Score:3, Funny)
Re:Damnit! (Score:4, Funny)
There's a great Scene in Breaking Bad where Jessee tries to dispose of a body in a tub using hydrofluoric acid and a disgusting cheese body gloop falls through the ceiling after the HF eats the tub.
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I wonder (Score:5, Interesting)
Re:I wonder (Score:5, Insightful)
That being said, it is far worse to convict an innocent individual than to let a guilty man go free.
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Except now we're all going to be fingerprinted so they can match these rogue fingerprints.
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Re:I wonder (Score:5, Insightful)
Re:I wonder (Score:5, Interesting)
Just imagine all the suspects involved with fingerprints on the brass cartridges:
1. The packing person who took the cartridges and placed them in a cardboard box.
2. The shop owner who took the cartridge out of the box to ensure it was a match with what the customer wanted.
3. The actual person who loaded the weapon.
If one fingerprint overwrites another, then it's not a problem. But what if the corrosion effect is additive and you get two patterns merged together. Would forensic experts be able to separate the two or would they get false positives with other fingerprints of innocent people?
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Re:I wonder (Score:5, Informative)
Cartridges are not serialized. Even lot numbers are just marked on the carton, not on the cartridge, and any given production lot can end up being split between many, many sellers. With a shelf life measured in decades, a box of ammo might sit around on the shelf for a long, long time, and may change hands many, many times before being used. It's not even that unusual to use surplus ammo dating back to WW2 or before. A brass cartridge might have the year of manufacture stamped on the head (more likely for military ammo than for civilian ammo), and there are no markings at all applied to the projectile.
In general, it would be pretty hard to trace an arbitrary cartridge back to a particular seller or buyer without other evidence. About all that you can determine from a shell casing found at the scene of a crime would be the manufacturer, caliber, possibly the original year of manufacture (and that shell casing might have been reloaded numerous times after that), fingerprints of one or more persons who have handled it, and it may be possible to determine that it was fired in a particular firearm if (and only if) that firearm is recovered, and has not been modified, repaired, serviced, upgraded, or even fired a large number of times since that shell casing was fired in it.
You probably will not be able to trace a cartridge to a buyer or seller unless the box it came out of is also left at the scene with its credit card receipt taped to it, and even then it could be argued that a receipt indicating that particular brand and type of ammo (if the brand and type is even listed on the receipt) didn't correspond to that specific box of ammunition, and/or that the shell casing did not come from that specific box. It would be much like trying to match an individual paper napkin to a particular package, manufacturer, seller and buyer.
The FBI used to claim to be able to match a bullet to a specific manufacturing lot based on chemical analysis of the bullet's lead, but that technique has since been shown to be bogus.
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Plenty og scope for fingerprints to get on a cartridge. Especially if you were to have s
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True. The firing pin's imprint in the primer (which gets replaced with a new primer for each reload) would be valid, but things could be complicated by multiple sets of bolt face imprints on the case head.
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Just imagine all the suspects involved with fingerprints on the brass cartridges:
1. The packing person who took the cartridges and placed them in a cardboard box.
2. The shop owner who took the cartridge out of the box to ensure it was a match with what the customer wanted.
3. The actual person who loaded the weapon.
It's not that big of a deal to eliminate individuals once the prints have been pulled. If a crime is committed in say Idaho, and the shells were manufactured and packaged in Virginia and prints from A (criminal), B (packager), C (store owner) are pulled, it's trivial to eliminate the B set as being irrelevant.
Under normal circumstances, person B will be flagged as a suspect (because her prints are on the brass) and once it is determined that she was in Virginia when the crime was committed, she will be
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That is WORSE than unhelpful, because you then have to try and establish that they are unrelated to the case at hand, without knowing an identity.
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Well this could be used to exonorate people. I mean you can make a reasonable doubt argument that.
Hey if I shoot him then you should be able to find a finger print on the gun, given the whitness says I did not ware gloves. Since you can't its resonable the whitness is lying or mistaken as they often are.
This could be a big help to the falsely accused.
Re:I wonder (Score:4, Insightful)
Digital photos can still be evidence! (Score:2)
The requirements are pretty though though:
You need a special camera version which contains firmware (hopefully tamperproof) which uses public key crypto to digitally sign each photo as it taken, making it possible to prove that the photo file hasn't been modified at all.
One example is the Fujifilm IS Pro which can be delivered in this form:
dpreview Fuji IS Pro review [dpreview.com]
Terje
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If the feature actually works (keys/crypto not broken etc), you know that photo or tampered photo is unlikely to be created by someone without access to that key.
But if you have had access to the camera, you might have the key.
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This really drives one to another issue. The longevity of the fingerprints will remove their value. All a finger print proves is proximity. As long as a finger print is there, it proves nothing but attendance.
Fingerprints are just a tool.
Traditional fingerprints can be used where time you are trying to determine if someone was there recently. This new technology may be useful in a case where the suspect claims to have no connection with a place or object. They'd need to be used more carefully and their use
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"That being said, it is far worse to convict an innocent individual than to let a guilty man go free."
At a one/one ratio, but some friendly casualties are inevitable. We accept a certain baseline of victims and injured/KIA police as the cost of fighting crime. We also tacitly accept a few wrongful convictions...
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Would you feel the same if they would put you into jail for many years for something you haven't done?
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My "feelings" are not relevant to the facts, which I noted above. While it is the duty of law enforcement to try to avoid punishing the wrong people, it is not rational to expect that it will never happen.
I would be trying everything I could to get any wrongful conviction reversed, but I would still understand that ALL processes have an error rate which, while it can be reduced, cannot always be reduced to zero.
Re:I wonder (Score:4, Interesting)
"That being said, it is far worse to convict an innocent individual than to let a guilty man go free."
At a one/one ratio, but some friendly casualties are inevitable. We accept a certain baseline of victims and injured/KIA police as the cost of fighting crime. We also tacitly accept a few wrongful convictions...
Re:I wonder (Score:5, Informative)
This question was raised and discussed by Alexander Volokh in n Guilty Men [ucla.edu].
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Cheers.
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There are exceptions of course in cases where you have a group of people and you pick up one or two extras(though the odds that you'll pick up 3 people get a 4th and that 4th isn't guilty and you didn't let one of the other 3 get off easy).
So realistically the only beneficial way(read innocent men get
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I think any ratio of falsely convicted innocents is "unacceptable". Unfortunately in reality it is impossible to achieve this ratio. So there's no answer to question of what amount of innocents convicted is acceptable.
Therefore I think the better question is, when does the ratio of criminals not getting sentenced become unacceptable. IMHO that is an aswerable question, and then the ratio of innocents convicted should just be minimized given the current technology and resources.
Re:I wonder (Score:5, Insightful)
"We also tacitly accept a few wrongful convictions..."
Speak for yourself.
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Tell that to the next rape victom.
Life isn't black and white, I loath short high and mighty quotes that try to paint it that way.
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Or to the innocent man/woman locked up for life for a case of mistaken identity...
The question is, at what ratio of imprisoned innocents vs freed guilty is suffering minimized?
Re:I wonder (Score:4, Insightful)
Perhaps a better question would be: are you willing to take the risk that the person you're locking up may later be proven innocent, knowing that if that happens you'll have to pay restitution for all the pain and suffering you've caused them (not to mention lost wages, etc.)?
The "correct" balance between false positive vs. false negatives is far too abstract to have any objective answer. This is a situation that calls for a feedback loop, punishment in proportion to the effects of an incorrect judgment. The standard of evidence would then take care of itself. In any event, it is only right that one make up for harm done to others, even when one thought one was doing the right thing at the time.
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Sure, but the other side of the coin may be there as well..."are you willing to let this murder/rapist/thief go to commit more crimes, create more victims" if you're wrong the other way...
Locking someone up who's innocent is bad. So is allowing a murderer to go free to kill again. I'd be nice if we could always do the right thing, but in the absence of that, I say we try for 'least suffering'.
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Sorry, but I'm not willing to sentence someone before they commit a crime just because I see them as a potential threat. Justice requires that the punishment fit what they actually did to you, not what you or others expect them to do in the future.
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Oh, I'm not advocating locking someone up before, I'm saying that when you have a suspect for a crime, there's a trade off between letting him go if he's the guilty (murderer/rapist/thief) and he kills/rapes/steals again (causing suffering among his victims), and locking him up if he's innocent (and an innocent man/woman suffers). You can guarantee that no innocent person gets locked up, by not locking anyone up, and you can guarantee no guilty person goes free by locking everyone up. The right thing is to
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In many cases it is the same coin. In that you are imprisoning an innocent person whilst letting a guilty person go free. The only exception would be where no crime actually happened. Which appears most likely with rape...
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With such restitution possibly not fully making up for their loss. Especially in the UK where they are likely to have "board and lodging" deducted.
The "correct" balance between false positive vs. false negatives is far too abstrac
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When you've killed him, it's too late to do anything. IMO it's the single best argument against death penalty in a judicial system.
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Try stating that once you're the innocent in question.
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Another fairly absurd alternative is filming each and every time you fuck someone or make them sign a contract beforehand.
Re:I wonder (Score:5, Insightful)
Let's take the harm suffered by letting a guilty party go free. We can call it G. We will assume this is a positive value, since I think we can agree that letting guilty people go free is harmful to society.
Now, let's take the harm of imprisoning an innocent man, which we will call I. Also positive, since putting an otherwise useful member of society in jail for no reason is something I think we'll agree is harmful.
So let's look at the harm caused by each of our actions. Letting a guilty man free is of course G, as by our previous definition. Now to calculate the value of imprisoning an innocent man, we take our value I, and add G. Why? Well, in convicting the wrong man, we have inherently allowed the guilty party to go unpunished. So we can conclude that that G is less than I + G, i.e. it is better let a guilty man go free than to punish an innocent man.
Didn't think of that, did you?
So while convicting an innocent man might give you the opportunity to go tell that rape victim, "It's ok, we got him" it's a lie, and that lie not only destroys an innocent mans life, it lets the real rapist go free.
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If there was a real crime commited then jailing an innocent person means that someone who is guilty has gone free. The harm starts as soon as an innocent person is charged and any police investigation either stops completely or becomes entirely focused on finding evidence against that person. Even
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Just because someone isn't breaking laws doesn't mean you necessarily think their presence in society is useful. In that case the obvious desired outcome is to round up the guilty and innocent alike from the "useless" part of the population, which means anyone from the wrong ethnic or religious group, political dissenters, people who voted for the wrong party, computer geeks who ask too many questions, etc. So, I think trying
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You have someone who's been convicted of something ; you institute a second (third, or whatever) re-examination of the forensic evidence gathered at the scene using this technique (it's probably far too late to get new evidence now) ; you find no fingerprints assignable to the convicted person, and petition for a release.
The first appeal judge say to you "Absence of evidence is not evidenc
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It could also be a huge disaster for police departments. Thousands upon thousands of individuals appealing for reexamination of fingerprint evidence could swamp crime labs.
Yeah, that won't be much of a problem... they'll just ignore it. Just like they've done in the past when it's been made obvious that the state has accepted evidence presented by "experts" that actually know nothing.
This [findarticles.com] article talks a bit about what a problem it is. I don't see the specific case in it that I was looking for though - I know there was a forensic "expert" at hair and fingerprint analysis that convicted hundreds and hundreds of people and the state refused to systematically reexamine or rev
Re:I wonder (Score:5, Insightful)
how many peices of evidence for earlier crimes we can now find a print where we couldn't before?
How many pieces of evidence are now ruined, because there wasn't a careful procedure followed in the chain of evidence where nobody touched it? A bullet casing or bomb fragment being criss-crossed with fingerprints isn't exactly going to make this technique any easier.
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That's not going to slow anyone down.
it will be easy to run an algorithm that separates one fingerprint from another - ESPECIALLY if they're blatantly differing fingerprints and one of them exists multiple times on the same object.
This would be like trying to read the stamp on an envelope after the post office has notorized it.
hardly cause for alarm.
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I'm surprised this hasn't been done before. Anyone who has handled a carbon steel framed firearm that's blued or parkerized but not painted or otherwise coated can tell you they etch pretty damn well from sweaty fingerprints. I've also seen brass shell casings with fingerprints, the prints turn black with age. There are now lacquer or polymer coated steel shell casings that would limit this effect. They're made of those materials because of cost. Many modern firearms are now coated rather than blued or park
Too Bad Fingerprinting is Useless (Score:3, Interesting)
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Quite right, but a sensationalistic subject line such as 'Too Bad Fingerprinting is Useless' tends to attract karma.
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You could have come up with a better webpage than that. The Shirley Mckie [slashdot.org] case is a good place to start. The original event happened in January 14th, 1997. A decade later, a public enquiry is only just about to start in September 2008. There is a Wikipedia entry [wikipedia.org]
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I don't know what that means. Fundamentally I do not agree that a religion can 'act' like a race. No race in it's entirety acts in any one manner so acting like a race is impossible.
'Acting white' or 'acting black' are nonsensical phrases.
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Wooden bat never fails (Score:2)
I'll stick to the wood bat as weapon of choice for murder, it can easily be disposed of with fire.
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Acually, it's a Roald Dahl story, only later filmed by Hitchcock:
http://en.wikipedia.org/wiki/Lamb_to_the_Slaughter [wikipedia.org]
Until five minutes ago I didn't even know AH filmed it.
Wrong game (Score:5, Funny)
He's not playing Rock-Paper-Scissor, he's playing Bat-AcidSoakedSponge-Saw. The hand motions are a little strange though.
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Wouldn't that be a given in an area full of icicles?
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Not forgetting to put a drill down the barrel just in case they do find the gun.
How Long Do They Have to be There (Score:5, Insightful)
Corrosion is a complicated subject (Score:5, Interesting)
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Or what if you "clean" the gun with something corrosive?
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Passvation layers? (Score:2, Insightful)
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wear gloves (Score:2)
I wonder how sweaty one should be, for how long the finger should be on the surface of a bullet for it to leave such a corrosive mark, and also whether this applies to other metals, such as stainless steel?
In any case, wear gloves even while putting bullets into your guns ;)
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Blah, lost post the first time i tried this.. anyone else have problems with safari blowing up on trying to post?
Be sure to wear you gloves when building bombs too, and use a "clean box" so you don't leave any DNA behind.
As far as bullets, if you only touch the cartridge, you wouldn't be leaving any prints on the bullet.. You are taking your cartridges with you and not leaving them at the crime scene, right?
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Seeing the wood for the trees (Score:5, Insightful)
Archaeology Applications (Score:5, Interesting)
Does this mean that we can see the fingerprints of people that handled old metal objects/chalices/swords/etc.? Maybe it would just be an item of curiousity to have a copy of Julius Ceasar's or Queen Elizabeth's fingerprints but I would put it on my wall! Maybe we could learn something about how fingerprints have changed (or not) over the course of history.
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In theory, ya.
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corrosion? how much? (Score:3, Interesting)
ok, we all have some corrosive sweat or alike in our skin, but that doesn't mean we all drop out the same amount of corrosive liquid.
there are people who can not touch a motherboard 'cause it would end with a big mark on the metal, it could even lead to malfunction, this is well known in the industry... I guess they borrowed their idea from here...
but how much of this corrosive is required for this method to work?
also, saying "metal" is saying all and nothing... there are metals that corrode easily, others that don't...
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WTF, haven't we known this? (Score:2)
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JFK (Score:2)
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As was the presidents' brain.
And anyway, the files are covered up by the government for [life expectancy at the time] after the events, 2033 I think. So "now"... not so much.
SANDPAPER! (Score:2)
SANDPAPER!
fail!
Not new (Score:2)
Simple solution (Score:2)
More forensic 'science' vaporware (Score:2)
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As my lawyer friend says... the court of law doesn't necessarily judge based on who actually did the crime. It judges on who has the better story.
That said, the story still has to be based on a fact.
So... fingerprints are even recoverable from... (Score:2)
Sorry, pun intended
Loading != pulling the trigger (Score:2)
Wow! Just loading a firearm is prima facie evidence of murder!
So if someone steals my loaded pistol, or even a pistol and ammo I've handled, I'm guilty of murder. Nice.
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Err... expensive? buy a tub of marine salt (the kind you use to mix for marine fish tanks) and dump the weapon in that for a few weeks - ideally heated and then place in a bag and leave to corrode...
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If you're going to police the area for your spent brass after you shoot someone, you're better off using a revolver, which won't toss empty cartridges all over the place. Beyond that, if you're doing it someplace where you don't already have your prints all over the place, thin gloves will keep you from leaving fingerprints in the first place... and you can dispose of the spent brass and gloves in widely-scattered places unrelated to the crime. If you're near the ocean, toss them in; the effect of the ions