1. Next-of-kin frequently screw up height estimates of missing family members. People 18 to 44 generally overestimate the height of the missing person while people 45 and over tend to underestimate height. The theory: people 45 and over estimate height based on how tall they used to be, not how tall they are (due to age shrinkage). Adjust height estimates accordingly.
2. Cocaine adulterated with different powders create different crystalline structures in micro-crystal tests. Pure cocaine crystals look like snowflakes (to this layman), with sharp white crystals growing out at 90-degree angles. Sugar makes clusters of circular, white crystals that look like white blots. Levamisole makes colorful circular crystals that look like little oval rainbows with black hollows in their centers. Levamisole, an agricultural de-worming agent, is getting harder and harder to find in the U.S. (even for forensic scientists) as chemical companies take it off the shelves to keep it out of cocaine.
3. Forensic entomology is an increasingly complicated science, as biologists pinpoint time of death and even place of death by the bugs living in and around corpses and precisely how old they are. Corpses in wells, in woods, in shallow graves—lots of photos of decomposed corpses and their larvae at the AAFS conference.
4. Multiple stab wounds usually indicate homicide, but investigators in a Florida case identified a suicide who had stabbed himself dozens of times all over his body—neck, chest, arms—by a) the fact that he wasn't wearing a shirt (suicides tend to uncover the area they'll be stabbing), b) a history of depression and mental illness, and c) the way the wounds showed trauma from the blunter parts of the blade. Homicides show more pointy sharp-insert action (just stabbing straight in), while suicides, because they tend to hesitate, have some shallower wounds and wounds that show more exposure to the blunt edges of the blade. (At least that's what this layman was able to gather from the presentation.)