I suppose this is more of a tip than anything else, but it is research related so I hope I am posting it in the right place. If any of you are crime fiction writers like myself, i've found that when it comes to researching the more scientific details of a murder or crime scene etc, a great place to go for some quick and free expert advice is forensic science forums.
When researching a book i'm currently writing recently I found all the answers I needed on the Forensics & Crime Discussion Board (I won't post any links, cos I know that's against the rules

).
I hope that's of some use to any of you crime fiction writers who, like me, have trouble with the tricky sciency bits =P