Murder weapon, or not, I still think there is a reasonable possibility that one of the cops ran off with the Ramseys' flashlight and left a dirty one behind.

I also wonder if the flashlight currently in the BPD evidence locker is the same one that went missing for so long.

Then there is the reported lack of fingerprints on the batteries...

I suppose it could be just coincidence, but it would seem possible that the flashlight has been swapped or tampered with at some point since the night of the murder.

What cop would admit to accidentally leaving the scene of the latest "crime of the century" with the murder weapon thrown carelessly in his trunk? And, if that were the case, what cop wouldn't want to get his own flashlight back real fast?