[woodruffw]

That's where the parallel construction part applies: ShotSpotter lets the police do "vibes based" policing (to put it nicely), and then parallel construct their way backwards to a "legitimate" source of evidence.

(If I'm being pedantic, "fruit of the poisonous tree" usually refers to illegally obtained evidence, which ShotSpotter is technically not. It's purely a source of investigatory pretext.)

[feet]

Correct, it's usually the evidence obtained in the parallel construction phase that was illegally obtained