If you're a fan of CSI, beware, this may be a spoiler for a future episode. But for the rest of us, it's just news.
A new technique can find drug metabolites in fingerprints. What they do is put drug-specific antibodies onto magnetic dust, they sprinkle the dust on the fingerprint and brush it away like normal. When a solution is applied to the fingerprint, the antibodies will glow if there is, for example, THC in the fingerprint oil. The shape of the fingerprint is retained and it can be traced back to a specific person just like normal.
I wonder what other metabolites would end up in fingerprint oil: would it be possible to read intense emotion from the chemical residue left behind? Or steroid metabolites from a baseball player's locker handle? I'm sure there's some touchy privacy issues here too.