For example if you use a gun to kill someone how could the bullet possibly be linked to you thousands of guns use the same caliber or a knife even though you would feel terrible looking at the knife wouldn’t it make more sense to just clean it and continue to keep the knife in your home so it make sense that your dna is on it? in movies people always feel the need to get rid of the weapons but i think it would make more sense to keep it unless there’s something i’m missing
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Because it is just one more piece of evidence that could be used against you, given high-tech forensics are now possible in many jurisdictions. Better to remove that one extra piece of potential evidence.
Edit: don’t do crimes, kids.
A bullet can be connected with the weapon hat shot it with a very high probability. There are fingerprint like scratches from the barrel on the bullet.
A knife is not that easy but width, thikness and shape can be matched with a stabbing wound as well.
So bullets are actually slightly larger than the barrels they are fired through so when the bullet is being passed through it actually crushes a little and every barrel is slightly different so a bullet can be traced to a specific barrel
Dpeends. It’s not about keeping from being found at all. It’s about preventing someone from proving that you were the one if they find you otherwise.
For example say a security camera sees you and a couple other guys near the murder site at the appropriate time. That’s enough suspicion to get a warrant to search your place, but not enough to prove you did it, but if they happen to find a knife you kept with traces of blood in the wood grain of the handle, or a gun whose rifling pattern matches the bullets (which is a forensics technique that can strongly link a specific bullet to a specific gun) then you are in trouble.
You can clean the knife sure, but maybe you didn’t clean it well enough. And maybe you can scrape the barrel of the gun to fouled up forensics, but then the fact that you scraped out the barrel is unusual and counts as evidence itself.
Guns are mass manufactured, but they’re also all a little unique. A bullet recovered at a crime scene absolutely can be linked to a specific gun based on the way the rifling in the barrel has scored the bullet.
Every gun has a somewhat unique barrel “fingerprint” that forensics investigators can record if they recover the gun itself.
If your gun’s fingerprint and the bullet found in Jimmy Knuckles’ skull match, you’re fucked.
A smart criminal will *destroy* the weapon in question, making it impossible to ever become a piece of evidence against them.
The guns you refer to tend to leave unique marks on the bullet and casing (made by a gun when fired) that could be matched up to a particular firearm. If the gun used in the murder is missing, *then* you could use your “one of thousands” argument.
The knife you described could still have DNA from the victim on it or marks on it made during the stabbing, like a rib or arm bone scratching the metal. Maybe even a whole broken-off tip.
It’s usually better to have the murder weapon missing **to introduce doubt**; its absence can always be explained away as having been lost or stolen.
Every weapon has a unique signature, like a fingerprint or a shoe print. The imperfections and wear and tear mean that when examined under a microscope, the marks left by the weapon can be used to identify if that weapon was the same one used in the murder.
For a gun, bullet forensic experts will examine the shell casings for lands and grooves – markings on the casing made by the rifling of the gun. Even though there may be thousands like it, the wear on the rifling of a gun is unique. Forensic experts will discharge the suspect firearm, match the casing grooves with the evidence, and establish whether the murder bullet was fired from the same gun. Similar with knives: the blades will inevitably have chips and cracks that will appear in forensic testing.
Having the murder weapon in your possession is pretty much giving yourself a big red target for investigators. If the victim was killed by a 9mm gun, and police find that you have a 9mm gun, that’s going to be taken and tested, and now you have to explain how you happen to have the exact gun used in the murder. In contrast, getting rid of the weapon introduces two hurdles. Firstly, the police have to find the murder weapon. Secondly, the police have to establish the link between the suspect and the murder weapon. It can be much more difficult to establish guilt beyond reasonable doubt if the murder weapon is not present.
Hence, murderers will more often than not want to dispose of the murder weapon to create a break in the evidence so that it doesn’t link back to them.
>For example if you use a gun to kill someone how could the bullet possibly be linked to you thousands of guns use the same caliber.
Others have noted the forensics around this (which I agree are likely exaggerated in terms of accuracy of match), but another thing to note is that there may be thousands of a particular gun in a city, but very few of those people will be linked to the homicide. If there’s someone with motive to kill the victim, the victim was killed with a .44, and the suspect has a .44 that was recently fired, the last piece of evidence is really helpful in comparison to there being no evidence of the suspect owning any weapon other than his grandpa’s rusty shotgun that he inherited but never fired.
It’s probably less important with a totally random crime where there’s no link, but then why take chances with the possibility of life in prison?
It used to be they’d send the gun to the FBI who had a huge backlog, so it didn’t happen too frequently. And the old methods were kind of questionable as to their accuracy.
As I understand it’s only in the past 5 years there’s been a big jump in the ability to really match the bullet to the fun that fired it, but they have a very high degree of certainty now.
You’d want to destroy the firearm, you could cut the barrel or hammer in some kind of wedge to alter the rifling.
I did consulting work a few years ago in a case where the criminal and the police all had the same weapon using the same ammo. I was asked to review all the body and cruiser cam footage and map which bullets came from who. They don’t always test the ballistics in the lab.
Because if you’re a suspect, they can get a search warrant.
If they find a gun in your possession, they can compare its ballistics to that of the bullet(s) used in the crime and provide x% probability that your gun (the barrel of a gun tends to leave a more or less distinctive pattern on bullets fired from it) was the one used in the crime. Failing that, they can usually tell based on the wounds what caliber was used. That, plus evidence of powder residue or similar on your hands, can count as pretty powerful circumstantial evidence against you.
If you can ensure the weapon is not available to be examined or entered into evidence, it’s one less piece of evidence connecting you to the crime.
That said, if they know you owned such a gun, but you can’t produce it, that’s going to count against you, too. There’s no national registry in the U.S., so it’s not like cops can just check and say, “Yeah, records show OP owns a 1911 with serial number xyz; where is it, OP?” They’d have to have testimony from somebody who knows you own it or something.
Also, you can’t just “clean” a knife. If it was used to attack someone, their blood is likely to be in EVERY little crevice, including right up inside between the hilt and the tang. You could, e.g. soak it in bleach for a while? I guess? That wouldn’t stop them matching it to the wounds on the victim if the knife was in any way unique. If it was just a bog standard kitchen knife, well, it could’ve been anybody’s kitchen knife – literally every house has those. But if it was, say a military-surplus ka-bar/old bayonet, or an unusual shape or something – those are less common, and would affect the shape and character of the wounds inflicted. A good forensic pathologist…
idk. Just maybe don’t commit violent crimes in the first place and it’s a non-issue.
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