One crime scene is the body itself. This crime scene will also have the victim’s ID probably and the bullet. The scene will almost certainly be found. The TTD will vary from immediate to a few days, and is hard to control for the sniper.
The second crime scene is the sniper’s hide, where he shoots from. Its harder to find this CS.
The practical distance limit for shooting is 1 mile or 1600 meters. This distance extends in a sphere around the body. The officers would be looking for footprints, shell casings, and eye/ear witness statements.
There have been many, many successful snipers in the US. They succeded in….….. the short term, only to fail in the long term. One must not neglect to destroy evidence – and especially the gun.
A sniper loves his gun; it’s like his right hand. It still has to go. A gun is not worth more than one’s freedom. It has to be totally destroyed; not sold, not throw away.