You missed the part where they illegally used private data to ascertain every individual in the area.

Then cross reference et cetera.

There was the illegal part, at the beginning. The police could have just put in the effort and checking on information from various channels, determined the same information. However, that requires effort and occasionally intelligent actors. So, instead, they do the illegal part, scrub that from the record, and pretend they figured it out, with a pencil and a pad!