See, I kind of believe that there's an explicit acknowledgement among movie producers that because people expect to suspend belief about the existence of paranormal nonsense, the filmmakers have much more leeway to fudge or even completely disregard key details about the real world parts they depict in ways they could never get away with in a real movie, and that goes double for what happens in police investigations, court proceedings, business offices, college campuses, you name it.
In fact, I firmly believe that a high percentage of the most avid consumers of horror movies actually believes paranormal definitely exists, which means they almost certainly don't have much of a clue how police stuff etc. actually works, so the filmmakers can depict it in practically any way they want and not have to worry about getting called on the carpet by Internet scolds for it. And even if they are, well, all they have to do is reply hey, it's a movie about aliens/voodoo/super killers/etc., lighten up, d*ck. Put the scolds on the defensive, make them the wet blankets. Filmmakers would totally get support from all the non-scold fans on it.