This is non-sequitur. "Investigating crimes" entails knowledge that a crime has actually occurred, and deliberately seeking information specifically related to that crime; "fishing for circumstantial evidence" does not.
Being located in an area of a crime is circumstantial evidence. Any info on what drivers license plates drove by a camera is absolutely circumstantial evidence to a crime in the area that is known to have occurred, almost definitionally.
Being located in an area of a crime is circumstantial evidence. Any info on what drivers license plates drove by a camera is absolutely circumstantial evidence to a crime in the area that is known to have occurred, almost definitionally.