Also as a biologist I gotta say I’m incredibly fucking dubious about how trace DNA is used as evidence

Like, contamination is just so easy. We had to keep a specific room where you couldn’t even touch the light switch without gloves to avoid contamination. It’s sooooo easy for stray DNA to get in your shit. And thats where the stuff I’m looking for is in relatively large pieces of tissue.

It’s the perfect mess, it sticks around long enough that it can ruin your shit, but also fragile enough that you have to be careful to not destroy it.

I just don’t trust that the tiny bit of DNA you found on an item on the street of midtown manhattan means fucking anything. I don’t feel like that tells you anything more than “This guy was in the city in the last week”

Oh you swabbed the shell casing? How do you know it didn’t roll into a puddle of spit on the sidewalk? How do you know that DNA came from the shooter? You don’t know shit.