calling on CSI fans/freaks

In a few weeks, we're holding a lock-in for our 5th & 6th graders. the theme they picked was a CSI night. So my thought was to do something like a nurder mystery, but make it like an episode of CSI.

I need ideas for:

the crime
the victim
the suspects
the evidence

let the brain juice flow friends..

give me what you got..

thanks