Page 1 of 1

Methods of Identification

Posted: Thu Jun 22, 2006 4:38 am
by EmmaC
I was wondering what's the first thing you do when you have a latent print to analyse?

Do you scan it in and then pick out areas of interest and then run it through a program like AFIS.

Will AFIS give you one print or a selection of prints? Then do you physically compare it with the selection?

The problem I have is though we have been briefly shown how to compare prints I'd like to know how it's done in the real world.

Please can this not turn into scathing attacks on people and their methods of analysis. There's too much of that already in other postings.

Can I just thank those that have replied to my other posts you have all been really helpful.

Sequence of events - latent prints.

Posted: Thu Jun 22, 2006 5:00 am
by Cindy Rennie
Every department has standard operating procedures when it comes to latent fingerprints, but there are some basic steps that we all have to take.

(1) analyze the latent fingerprint and determine if there is enough clear detail to individualize.

(2) Compare the latent fingerprints to those of the victims/suspects.
(Elimination prints will come from victims or anybody else who had legitimate access to the area).

(3) determine if the latent is of sufficient quality/quantity for an AFIS search.

(4) If suitable, search on AFIS.

When I was doing the AFIS job, I would pick the best possible latent and search it first. If I made an identification, I would compare that suspect to all of the other latent fingerprints. If I had some latents that did not belong to that suspect, I would search them on AFIS next.

(Some technicians loaded ALL of the latents on AFIS before checking any possible matches.)

We now have LIVESCAN technology, and I know of at least one technician who scans everything into AFIS and THEN decides if it is of sufficient quality and quantity of detail to individualize. He claims that scanning takes no time at all and helps him make a decision.

(5) when the possible matches are presented on AFIS, compare the latent to the suspects on the screen. If it appears that they came from the same source, pull the "hard copies" of the known fingerprint from the file and compare them to the original latents. If you reach an opinion that an identification has been achieved, give the file to another qualified member and have them confirm your identification.

(6) once confirmed, give the file to the Scenes of Crime officer who attended the scene and collected the latent, or the SOCO Case Manager (if the scene was attended by a SOCO officer). That person will examine and re-confirm the identification and send a report to the investigating officer.

(7) if a latent is searched on AFIS and not identified, it is kept in the Unsolved latent database and compared to every new set of ten-prints as they are processed. (Yesterday I confirmed an identification from a Break and Enter that took place in 1997 to a suspect arrested by us for the first time last week. They can run, but they cannot hide.......).

Posted: Thu Jun 22, 2006 5:06 am
by EmmaC
Do you use vectors and ratios when analysing fingerprints? is this what the software does?

Or is it purely pattern matching?

How detailed is Livescan? Does it give 3rd level detail?

Posted: Thu Jun 22, 2006 5:07 am
by EmmaC
Do you use vectors and ratios when analysing fingerprints? is this what the software does?

Or is it purely pattern matching?

How detailed is Livescan? Does it give 3rd level detail?