A Question for LEOs about fingerprints

[DD977GM2]

So in the oilfiled I work will all sorts of people. One guy on my rig was a gangbanger and 10 years in penetentiary for murder a few others are felons of some sort or the other and then there are law abiding guys. Well one guy said if you spray WD-40 on stuff cops cant lift finger prints...just curous if this is true? Id think it would preserve prints to some extent.

GM2

EDIT: First off the guy that actually said the comment is a law abiding citizen and an avid shooter. Im surpised he doesnt know about this site or others.

The guy that did 10 years, IDK the whole story nor do I care. I do notice he is a hard worker and genuinely wants to make a better life for himself, but like the statistic says....80% go back. As for his lawyer, IDK the story and dont much care to.

I also think it is hilarious all the urban legends that are out there to thwart the cops or forensics and I even get all the mumbo jumbo about firearms and people seem to come to me about this or that on gun legends. I always seem to get the one that in vietnam the VC used our ammo through their AKs and to this day you can still use the same ammo for ARs in AKs. Fucking blows my mind on that one and people actually believe it. I also get the same thing....45 if it hits you anywhere your dead and blows you back on your ass. Do people not know physics? Folks in the oilfield are hilarious and just make me stop and wonder how much the public truely feels urban legends are reality.

[Colorado Osprey]

LOL! Lots of rumors on the perfect crime circulate in prison/jail on how to get away evidence free.

Oil is what a fingerprint actually are.
There are many ways of lifting prints. Spraying something with oil after you touched it can eliminate some prints. WD-40 will actually make them permanent. WD-40 is mostly varnish.
Now in a liquid state when spaying, it can wash away the print, same as most soaps.

This also depends on the surface the print was left.

Wiping down what you touch can smudge prints to be un-readable.

Prints are interesting. On a piece of paper prints can be lifted a couple of hundred years later.

Prints are also a minor way to collect evidence.

Trace is left by everyone all the time where they have been. An example is dead skin cells. They contain DNA, better than a finger print. This is the same way a blood hound tracks someone or something. A lot of people watch TV shows like CSI and the like. Most departments don't have the resources and equipment that you see on TV. They are usually available only at a state level for special cases or a long wait for evidence tests.

If it were me, I wouldn't say a word to these ex-felons and just let them think they know best. That way if they do another crime, spaying everything down in wd-40 will make their case that much easier to prosecute. Statistics show that over 80% of felons will return to crime and return to jail.

[OneGuy67]

I've not heard of using WD-40, nor have I experienced that at a crime scene.

Thanks to shows like CSI, the general population has a false sense of what forensics can do, what their local police department can do and more importantly, the bad guys try to do things to thwart the efforts of law enforcement based on these assumptions.

As a patrol officer, I used to get a kick out of the drunks having pennies in their mouths when asked to provide a sample of breath. The urban legend was, the copper would lower the alcohol level reading. The more funny thing was, they wouldn't use copper pennies, but ones minted after 1984, which are zinc. Got to laugh at them twice.

[Graves]

Ever wonder... if he was so damn slick; how'd he wind up serving 10 years?

[TS12000]

These guys know there's this invention called gloves right? The criminal mindstate never ceases to amaze me. "Hey if you walk around with a can of wd40 da pigs won't be able to get your prints"

[BPTactical]

Ever wonder... if he was so damn slick; how'd he wind up serving 10 years?

The pitch..............A hit...............going, going.........gone!
Homerun by Graves!





Really though, his lawyer screwed him.....................

[Mtn.man]

Tell him to soak his finger in acid,,, that'll do the trick.

[GunsRBadMMMMKay]

Trace is left by everyone all the time where they have been. An example is dead skin cells. They contain DNA, better than a finger print.

I LOL'd at this...not that it's not true, just that there being enough skin cells on something like a gun to actually use for a dna test seems pretty far fetched. Then being able to prove where it came from if it was that small.......

I remember for a while there was a big press for DNA collection (to the point that they were talking about swabbing traffic stops or some bs). I wondered if they aren't recording the blood they take for DOT and other dept physicals...talk about sneaky, anyone know if they do this?

[OneGuy67]

I LOL'd at this...not that it's not true, just that there being enough skin cells on something like a gun to actually use for a dna test seems pretty far fetched. Then being able to prove where it came from if it was that small.......

I remember for a while there was a big press for DNA collection (to the point that they were talking about swabbing traffic stops or some bs). I wondered if they aren't recording the blood they take for DOT and other dept physicals...talk about sneaky, anyone know if they do this?

Just touching a firearm and having that area swabbed will most likely produce viable DNA. All they need is a couple of cells now. Very cool as far as I'm concerned.

Of course, just having the DNA being present doesn't necessarily mean anything. It doesn't date/time stamp the contact when the transfer occured. Additional investigation is needed to assist in the use of the DNA for prosecution.

They passed 'Katie's Law' in 2010 in which all individuals arrested for felony crimes are swabbed for DNA at the time of arrest. This has resulted in 9 sex assault cases, 3 criminal mischief cases and 28 property crime cases including arson, burglary, robbery and theft that were identified in the first four months of its start. This may be what you were referring to?

[Bailey Guns]

I worked in Booking in the JeffCo jail for a short time before I went to the Patrol Division. Of course, we fingerprinted all intakes.

Occasionally, when the right guy came along - usually an amiable drunk - we'd convince him we needed a "nose print" in addition to fingerprints.

Invariably they'd ask why. Our explanation was we had a lot of unsolved burglary cases and the nose prints were needed to build a database in order to identify burglars in the community. "Think about it," we'd tell the guy. "What happens when you put your face up against a window to look inside a building?" It's like a light would come on. "Yeah...you leave a nose print on the window."

It was pretty hilarious to watch a drunk take the ink roller and try to roll it across his nose without getting ink all over his face. It was even funnier to watch them try to "roll" their noses across the back of a fingerprint card.

Working in the jail sucked but there were some special moments.