There are odd bits of crime episodes floating around. Around here, some of the law enforcement agencies auction off seized firearms. One time I bought a Model 100 Winchester rifle that had little black pen marks on the stock. You know, like in re-runs of "Perry Mason" where in the courtroom Mason asks Lieutenant Tragg "if this is the murder weapon." Lt. Tragg says, "Yes, it was recovered at the scene and those are my initials on it" (pointing to some spot on the weapon). When I looked closely at these marks on the Winchester, there were initials, a case number, and rust red blood stains circled in fine time felt pen. Later, I contacted the county sheriff and researched the case and found that the rifle had been used in a double murder. That's probably not all that rare, considering the nature of firearms.
Another time many years ago, my dad and I went out to look at a 1954 Lincoln that was for sale. Sitting next to it was a kinda rare 58 Cadillac El Dorado Biarritz. It had a weird panel of duct tape across the top edge of the windshield. I asked the seller about it, and he said look at the glass on the inside. There was a bullet hole through the glass hidden on the outside by the tape. The car had belonged to a crime figure that got murdered outside his motel room. It didn't go on through as there was no hole in the leather seat.
That was the first time I'd ever seen duct tape; that musta been around 1972 or so.
In the case of the homicide Hoover, it's funny that the spent bullet would come to rest right on top of it. But a bullet has to come to rest somewhere.