yes they have magic technology that can 100% accurately trace denatured dna, which is why you should never commit a crime. actually no, they don't, and pretending they do has led to a number of miscarriages of justice.  its good for some things (like where the crime is attempting to press your dna on someone that doesn't want it...) but it isn't like on police procedural shows middle aged women watch. they might as well hit the enhance button the video and get a hi-res 3d model of the guy that shows a tattoo on the back of his neck.
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