CLPEX Chat Board

Has anyone used Wet Wop for processing items such as the non-adhesive side of tapes (such as duct tape), plastic bags or any other non-porous item? Does anyone know of any references for such uses? I have searched but am finding very little that is published. A few mentions to research done at the Home Office but nothing that I can access. Any help would be appreciated. Thanks.

There was an article in the JFI entitled "Developing Friction Ridge Detail on the Interior of Latex and Nitrile Gloves" that examined the use of Wet Wop on gloves.

"Developing Friction Ridge Detail on the Interior of Latex and Nitrile Gloves", John Pleckaitis, Journal of Forensic Identification, 57:2, (2007)

Forensic Scientist wrote:Has anyone used Wet Wop for processing items such as the non-adhesive side of tapes (such as duct tape), plastic bags or any other non-porous item? Does anyone know of any references for such uses? Thanks.

Did you ever find anything on this topic? I have some black electrical tape that was tightly wound around another object and accidently developed ridges on the non-adhesive side with wetwop. I am trying to find any experience other examiners may have had with this.

“Wetwop”, as with other powder suspension solutions, is simply a suitable powder being mixed with a suitable surfactant; a compound that reduces the surface tension between a liquid and a solid. In the case of adhesive tapes, the latent producing material is being held by the adhesive and attracts the suspended power while the surrounding adhesive repels the solution. If there are latent prints resulting from various substances that may be present on the friction ridges when touching a non-adhesive surface, these could attract the suspended powder in the solution and cause the latent to be developed.

SPR, another powder suspension compound, is recommended for non-adhesive, non-porous surfaces that have been subjected to water contamination.

Some latent prints are very TOUGH and if you were successful, enjoy.

It happens!!!

Our current policy lets us use WetWop on the adhesive sides of tape, and on latex/nitrile gloves. We are currently performing a full validation of its use on non-porous, non-adhesive items due to our initial studies on it, as well as its use on gloves. Our policy also currently lets us use a deviation from procedure to utilize WetWop on these items while the validation study is completed. I have used WetWop on a good many items, and have found very good results in those instances when I am all but certain that standard or magnetic powder just wouldn't help. It's particularly useful on very finely textured items, such as firearms, some plastics, etc. I've developed very nice prints on scales, firearms, non-adhesive sides of tape, vinyl/plastic bank bags, painted metals and the like. Right now, for us, its the last step for this type of processing, typically after CA and RAM. I've also found much better results, in general, from White WetWop than from black.

Hope this helps, and happy WetWopping.