Blood Divination

At the moment you first touch a sample of blood, you can determine who it came from with varying degrees of success. 

Roll D20 + Arcana OR Medicine Modifier. 1-3: The subject’s race only. 4-10: The subject’s race and gender. 11-17: The subject’s race, gender and approximate age. 18-20: The subject’s race, gender, age and name. Natural 20: See the exact moment the blood was shed.

You can do this at any time while touching blood, but cannot repeat it on the same sample. If another player also uses this cantrip on the same sample, the dice roll will remain the same, with their modifier of choice.

Note: I made this spell to use as a plot device for a murder mystery, and I haven't playtested it in any other context.