CA Development "Signature"

[Terry A. Smith]

Greetings;

Scenario: Cold case file with a fingerprint reportedly from an 'item of interest'. The print is now identified.

Problem: Was the fingerprint 'developed' on the item (subjected to CA fuming) at the time, or was the print a pre-existing 'patent' print with a 'white - ish' matrix ( ie, liquid paper, paint, etc. ). The original examiner admits that either possibility exists, that he simply may not have noticed the print on the item until after subjecting the item to CA fumes. It is the only fingerprint on the object.

Question: How would we conclusively establish that the fingerprint was, or was not, a cyanoacrylate impression?

I'd appreciate any thoughts.
Terry

[Charles Parker]

Will a fluorescent dye stain attach to liquid paper?

Will a fluorescent dye stain attach to a light colored paint?

Will a fluorescent dye stain only attach to CAE?

Interesting question.

[Peter Griffin]

Depending on the size of the item you could use an SEM. CA has a spaghetti-like appearance if done in a non-vacuum environment and more of a beaded look if done in a vacuum. If you don’t see either it wasn't fumed.
PG

[Les Bush]

I agree with Peter Griffin that an SEM will give you a non destructive visual comfirmation of CA morphology and also an elemental analysis of the composition. Taken a step further you could try non destructive XRF to analyse the area of development and again check for chemical composition. Last suggestion is to use a controlled laser beam to assist in separating the organic CA from the inorganic components in paint or other similar materials. Regards from oz.