CLPEX Chat Board

I'm researching for a book, and need to set up some fictional fingerprinting challenges for my investigator. Ideally, she wouldn't be able to visualize enough useable detail with the first or second method, but would have success with a third.

Two exhibits:

* a box cutter (with the handle wrapped in cloth tape), and
* a used condom (no biologicals -- the bad guy was having a bad day)

Glue-fuming would be one choice, but maybe it wouldn't be the first or best choice. I've read there's been some success with Gellifters after glue-fuming -- has anyone tried this?

Thanks!

1) Processes...yeah, generally we would fume the condom and (assuming) steel box cutter with CA. We would examine and then apply a dye stain and examine again with a laser/alternate light source.

There is another technique that could be applied (we don't have the instrument here, but they do in some labs, including, I believe in a lab in B.C. (Candian examiners can better fill you in as to which lab). This technique is Vacuum Metal Deposition (VMD). A quick google search should give you some more background on the procedure, but it's pretty cool (and expensive). We had just such a case (homicide) where we only got 1 print (to the suspect) after CA, dye, and then VMD. It was the VMD that got us the print. It was worth sending it out for the VMD.

2) In case you hadn't thought of it...yes the tape on the box cutter could be removed and processed, but sometimes forgotten, would be to take the box cutter apart and fume the inside too, specifically the portion of the blade inside that is protected and could maintain a print for a long time.

I could envision your investigator receiving the item processed, but realizing the person that processed it didn't take it apart and lo and behold you find a print on the corner of the blade inside that the latent print examiner could tell is a thumb tip and searches it AFIS. This assumes that the perp put the blade in himself...or...you could throw the reader off by having the person that put the blade in be someone different (contractor or construction worker), but the perp grabbed the cutter from the site...

OK, now I'm just riffin' good luck.

g.

Riff away -- that's how my job works. :)

I'm ahead of you re the box cutter blade, though. I do need my investigators to process the tape on the handle to find the suspect's prints, but I'm not making it easy and letting them find a blade inside. You know how the blades snap off in increments? During the crime, the suspect slides the blade out all the way and it breaks. He's smart enough to take the broken blade, but doesn't realize that a fragment -- the last increment -- has fallen between the cracks in the sidewalk to be found later.

It's never easy in real life -- why should it be in fiction?