Fingerprints - residual lenght of time

[BuckeyeGary]

How long do fingerprints typically remain on paper such as currency? Do the oils from skin evaporate? Logic tells me that there has to be a shelf life, but I have seen a reference to this. Any help.

[Too Long a Cop]

Dear Buckeye Gary, you will have to excuse the lack of enthusiastic response you have been receiving on this site, both to your first posting and to this one. The vast majority of readers here work in police services, and many are police officers ourselves. I have been in police work for well over thirty years. I remember at least two cases I personally investigated similar to the one you described in your first post. Funny, but both of those young women (both with husbands and children) proclaimed their innocence, too. The evidence showed otherwise. In neither case did I have any stake other than that of investigator - gather the evidence, present it to the prosecutor, let the prosecutor decide whether to go forward, and then testify in court if a case went to trial (neither did).

The point is this. When I was a young cop, I believed any story told to me with deep emotion by a "falsely accused" person. But in the years I have been a cop, I have been lied to so many times by so many "innocent" people that I hardly believe anyone any more. Sometimes I hate myself for being such a cynic, but there you go. That is who I have become.

As to the question of age of a fingerprint, there is a basic problem. We do not know what the original residue was that the fingerprint was left in. Was it oily? Was it oil-free moisture from the palm? Did it have foreign material such as hand lotion? And do not start thinking, "Well, we will just do a chemical analysis." That is not a practical solution, either. The bottom line is this: There is no reliable way of determining the age of a fingerprint other than it must have been deposited after the last thorough cleaning of the surface.

I would say to your wife, "Only you know for certain if you are innocent. If you are, beg the police and the prosecutor for a polygraph. On the other hand, if you are guilty get a good criminal defense attorney and cut the best plea deal you can. Do NOT continue to lie to your family and friends and do not prolong this mess. Get your s*** together, deal with it, and move on with life. Then, in the words of Jesus, "Go forth and sin no more."

[L.J.Steele]

"Too long a cop" is right -- the standard answer is that one cannot reliably "age" a fingerprint. There's too many variables. If a fingerprint expert tried to testify about age of a print, opposing counsel ought to object, citing several articles on this very topic.

I'd disagree with him (or her) in general about legal advice. Guilty or innocent, once the police have focused on someone in an investigation, they need competent legal advice. As I recall your earlier posts, you have an attorney. Your best bet is to work through him or her. The attorney will likely have contacts with local experts, and their conversations with the expert is protected from disclosure to the prosecutor.

If you do not trust that the attorney is doing a good job, then you need to work out the problem or find someone else. The attorney should be working on access -- generally, the prosecutor can place reasonable limits on access to experts and evidence, but can't completely exclude counsel and counsel's experts. (They can exclude others -- at minimum having the defendant handling evidence creates all sorts of risks of accidental contamination.)

[N G Morris]

Is it paper or is it currency you are talking about, Its unlikely currency is actually made from paper. It depends what county you are talking about. Try contacting you national Treasury and ask them. The currency from my country was once made from cloth impregnated with fat more recently it is made from plastic. This dictates how it is treated. It is true that most F/P experts will not state how long a print will last. However there are some who will look at the whole situation. In Poland, I understand they have given evidence on age numerous times. In certain situations the age of a print can have an educated guess!!!!!!!!!!! But this is very difficult as previously pointed out. Prints developed on paper have been proved to be over 50yrs old. On other surfaces any print left in greasy substrates will always last much longer than prints left in watery substrates. The question is how do you tell if it's watery or greasy?