What if someone is known to have committed a crime and police look at surveillance footage from nearby red-light cameras?

Or if that person is thought to have visited that location in the past, could they use that footage?

Which brings another question, what about facial recognition performed by a human? Investigators can presumably scour video or surveillance data by hand, but I guess just not by machine? Can they use face detection to simplify picking out faces? Zoom in and enhance?

It's very tricky when passing legislation to narrow in on the pernicious aspects of "facial recognition"