[LibKill]

Any gun experts out there?

I'm just semi-expert.

He is not using a silenced weapon or cartridges. A Cop was working a traffic accident accross the street from the last victim and heard the shot.

[icantbleaveit]

Is this the ONLY report of a shot that was heard?

[elhombrelibre]

Only subsonic rounds lend themselves to being silent. This round is travelling at around 3,000 feet per second. It's probably the 55 grain variety, but it may be the 70 grain weight. Still it's going to make a lot of noice.