| Author | Message | ||
     Ian Clingan |
Justin, I have recently used Amido Black on walls at a murder scene. This resulted in both palm and fingerprints being raised, retrieved and identified. One mark was in blood and the chemical treatment was used to enhance what was already visible. The others were invisible but raised using the chemical treatment when applied to where I thought the latents should be. The method used was as described in the PSDB Fingerprint Manual except that I didn't fix the marks. I never do, even in the lab. Over the years I have found that if the marks are dry there is no requirement. The method used on the walls was to soak kim-wipe in Amido black and gently place against the wall surface then gently wash down. If marks are noted continue gently to apply more Amido Black/wash until the required enhancement has been achieved. Regards Ian Clingan | ||
| Justin Bundy |
We at the MN BCA have been taking a closer look at how we have been enhancing bloody prints both in the lab and when responding to crime scenes. We are looking into how fixing/denaturing can be accomplished when using protein stains such as coomassie blue and amido black. We have found many sources that state different methods of utilizing these stains. Some that don’t mention fixing/denaturing at all, saturating/immersing the item in methanol for anywhere from 2 minutes to 1 hour, or baking/heating @ 100oC for anywhere from no time specified to 30 minutes and up to 1 hour. Some of these methods are difficult to perform while at a crime scene and taking back to the lab is not plausible (such as a bloody print on a wall). We were wondering what the SOP’s of others in the field are for the fixing/denaturing step and what their sources are for that step. Due to ASCLD, if the SOP’s state using heat at 100oC for 1 hour, we need to be able to measure that in the field which is not really practical. We are also going to do some of our own research comparing blood enhancers such as coomassie blue, DAB, amido black, and leucomalachite green. If anyone uses or knows of other blood enhancers that are worth taking a look at please let us know. You may contact me at: Justin.Bundy@state.mn.us Thanks for any help, Justin Bundy. |
