A Question for LEOs about fingerprints

[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.

[BushMasterBoy]

I think its easier to get away with a crime if you place both palms face down on a red hot stove top....tell him that!

[leatherneck448]

I think its easier to get away with a crime if you place both palms face down on a red hot stove top....tell him that!

I burned my index finger in caramelized sugar once, and the first pad of my finger was completely smooth for a few weeks. No print. In theory, it might work, but as other people have said, most people (including me) have no clue about forensics, so I wouldnt really know.

[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?