hypothetical paranoia question.

KC Slim

KC Slim

Fat Bastid
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Apr 22, 2001
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I know that many knives change hands here, but what I was wondering, is do you wipe your prints off of a knife you are selling to a stranger. I mean what if one of the knives you sold was found at a crime scene with your prints on it, what could happen?
 
A little paranoia is good... For curtesy's sake I always clean up all my knives before selling them, although that thought has occured to me as well. If i was selling to a knife buddy somebody I'd known for years, I'd feel better but for strangers I take extra care to clean up all my marks. The last knife I sold was a SF Commando Dagger which is illegal to carry around in this country - I made sure I obliterated all trace of prints on this one.

Andrew Limsk
 
Oh yeah... Wipe it all down for aesthetics as no-one wants to get a marred blade and I keep it inside the cloth as I place it back on the box for reasons of paranoia just like you describe. I haven't gone so far as to do all packaging, including purchase of materials, with mitts on yet though so maybe I'm not that bad. ??? ;)

Shawn
 
I'm no expert on criminal science, but two things make me wonder:

1. Does the technology to match a print against a computer database really exist, or is this a fiction perpetrated by television? Do you actually have to have a vague idea of who your suspect is to compare the print? (I'm really wondering about this, not being rhetorical.)

2. Unless the purchaser of the knife immediately went out and murdered someone, the fresh prints would probably be much clearer than older ones, and I'd think this would be apparent to the investigators.
 
how about the dealers,manufacturers prints?I think I tend to agree with Razoredj line of thinking.Good question though!
 
Razoredj- yes there is such a computer system. It takes the prints and converts them to a sequence of numbers using certain traits of the print. The computer then searches the database for a match. You prints have to be in the system for it to find a match.

Rich
 
Fingerprints are very corrosive. So, I always wipe off knives before giving them to a buyer since I can't be sure if I'm mailing the knife that there might be some delay in the mail and since I often can't be sure that the buyer will take proper care of the knife. I can't help him if his own fingerprints etch the blade but I can give him the courtesy of making sure that mine don't.

As for computer matching, Raz, I happened to read an article on that not to long ago (Scientific American, maybe). They do a computer-assisted match. A human operator translates the fingerprint into a series of numbers that represent specifc features such as peaks in the lines or place where the lines converge. This code goes into a computer and the computer finds all other known prints that match or are close. A human operator then sorts through those for an exact match.

As I recall, they said that a skilled operator could classify a set of prints in about five minutes. A typical set classified and run through the FBI's very large database produces on the order of a dozen or two potential matches. A skilled operator could then sort those and find the exact match (or rule out all matches) in about five more minutes.

A partial set of prints can take significantly longer since it will produce a substantially larger set of possible matches.

I have several scars on my fingers (balisong artist, you know) and so my understanding from this article is that matching my prints would happen very quickly and very easily.

This system of classification has been in use since well before computers. It's actually designed to allow hand sorting. If you've ever been fingerprinted, if for example, you've applied for a security clearance, concealed firearm license, BATF Form 4, etc, then you'll recall that you were fingerprinted at least twice. The FBI insists on two sets of prints. This is partially practical since if there's some disclarity on one, they can look at the other. But, the real reason for two sets is that historically they filed one card by name and the other by classification. This way they could find your prints given your name, or find your name given your prints.

The article also noted that fingerprints are made of liquids that flow, change chemically, and evaporate over time. The older the print, the less likely you are to obtain a match.
 
. . . . and in order to determine that they are your prints on the item, even if you HAVE been printed before, they must compare it with a database that actually has a record of your prints.
 
KC Slim. if you are worried that someone is going to commit a crime with a knife that you sell, just download your post and your transaction. That way there will be a record that you sold the knife. You might also want to hold on to USPS, UPS, receipts, deposit slips etc. that porve that you sold the knife.
 
No, as a matter of fact, I have never even thought that this could be a problem.I suppose this might be a problem if I were selling a knife to someone in the city I live in, but I doubt it. If I sell a knife to someone in Florida, for example, I think I would be able to prove I was no where around at the time.

You better be careful, I heard there are some people that are trying to frame you for killing some guy. What is really amazing is that I heard that they planned to buy a knife off you, kill this guy they hate and leave your knife at the scene. They will do this knowing that your fingerprints will be left on the knife. It is the most amazing thing that you would post something like this. Man what a coincidence.;)
 
paranoia is only hypothetical when you know for sure that they are not watching you...... :eek:

Regards,

Ed
 
well for the really paranoid among us, if ya have carried the knife any at all, DNA will be on the knife, which can be matched to your DNA, and ya will really have to clean it up to get rid of that......or ya can get a stupid jury like OJ simpson did lol.....personally i dont worry about it, if i sell a knife to someone in, say, ohio, and i live in texas, and someone is murdered, i will prob have an alibi lol...but i do see your point in all this for sure.....


sifu
 
razoredj,

i think there are three types of prints, loop, whorl, and arch. i believe the search engine for matching prints use the various locations of the deltas and centers in these print types as two end points for a line that "maps" the intersection of fingerprint patterns between them. this would yield a small string of data that would probably be a unique match for 99.9% of all prints out there, given a good enough resolution for that line. this is very efficient since the data match only has to be on a small protion of coded data, rather than the whole print itself (which is probably on the scale of 100x more data)if you use this line as search pattern to match against, it's very likely that you'll come up against its match in the database, or narrow the search enough for a small secondary search of a few patterns to yield the correct match.

i could be full of crap though. i'm not in LE at all, just extrapolating this from a fingerprint card and the recommendations that certain line patterns HAVE to be clear when taking the prints.
It makes great sense though, but i don't know what they would use to line up against for arch type patterns. anyone in LE care to elaborate? :D


toast
 
Once I was at a gun show and a guy I was talking to a guy who always loaded his weapon using surgeons gloves so his prints would not be on the shell casing. Now that's paranoid. He admonsished me for touching a round of some ammo I had never heard of the brand name before because my "print" would be on the case.
 
Quote attributed to Charles Manson (no idea if this is true)

"Paranoia is just a higher state of awareness."

Charlie is not someone to emulate, but that quote did make me think. Are sheeple the way they are because they are tactically unaware? It may not even be his. Somebody correct me if I'm wrong.
 
Just to add to some of the paranoia, people are being fingerprinted rather regularly now, and not even for BATF Licensing, etc. I was fingerprinted going into kindergarten, as are children at many public schools, in NJ, at least.

Joe S.
 
If fingerprints ARE corrosive (which I have also heard), and you have used your knife without wiping it down EVERY time, would wiping your knife with cloth take care of the prints? What if they "etch" the metal a little? What would you need to COMPLETELY take care of them?

Just hypothetically, of course... :rolleyes:
 
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