Paper or Plastic…How is Evidence Packaged?
Posted by forensics4fiction
Ya know, I don’t think I’ve ever seen a TV CSI package evidence in a paper bag. After all you can see the bloody gun unless it’s in clear plastic right. Well, what works for television doesn’t really work in real life. This is one of those “devil is in the details” type articles for your writing. As a general rule, criminalists don’t like wet evidence. Whether is blood, water, urine, or soda pop; wet evidence doesn’t do well in sealed plastic bags. That’s because plastic can not breathe, and if it can’t breathe it will grow mold.
This is especially important when you consider that some cases make take years to go to trial. That’s a lot of growing time for mold. Add to that the backlog of cases each analyst may have and you get a real recipe for disaster. Imagine an expert opening an evidence bag to do critical testing only to find a petri-dish of blood fed mold…yuck! For that reason most evidence is packaged in paper or cardboard just to be safe. Plastic can be used for dry documents or even dried bloodstained clothing, but only after dried.
Crime labs even have special cabinets where items can be stored safely while drying. These cabinets are very handy to separate clothing from say the victim and suspect, or items from separate cases. As you might imagine, medical examiners also use these cabinets as they deal with a lot of “wet” evidence.
In your story you could use this type of event as a major setback your characters must overcome. Image a suspect who gets away with a crime because crucial evidence was moldy. Will your characters be able to find other evidence before he strikes again? What about an innocent man who petitions to have evidence i the case tested with some new technology only to discover it is irreparably damaged. Any way you spin it, packaging can have long term implications for your case.
About forensics4fictionHi there. Thank you for visiting my BLOG for crime writers. I hope you will find it interesting. I would love to hear your questions and thoughts regarding forensics and criminal investigations. I hope that the information here will help answer your questions or ignite your imagination. I am a retired senior criminalist with 15 years of forensic experience. I have served as the president of the Association for Crime Scene Reconstruction, Rocky Mountain Association of Bloodstain Pattern Analysts, and the Rocky Mountain Division of the International Association for Identification. I am triple board certified in forensic related fields and one of only 40 board-certified bloodstain pattern analysts and 80 board-certified footwear examiners worldwide In addition to writing over 60 scientific papers, I have worked as the editor of the Journal of the Association for Crime Scene Reconstruction, been interviewed by and consulted for television, books, magazines, and newspaper articles including documentaries on the Discovery Channel and National Geographic.
Posted on June 17, 2011, in The Crime Laboratory and tagged detective, evidence drying cabinet, evidence packaging, fiction, forensics, murder, mystery, thriller, tom adair. Bookmark the permalink. 4 Comments.