Texarkana Moonlight Murders naming the beast what type of gun significate solving the case

The Texarkana Moonlight Murders, a term coined by the news media, were a series of unsolved murders and other violent crimes committed in and around Texarkana in the spring of 1946 by an unidentified serial killer known as the "Phantom Killer" or "Phantom Slayer". The killer is credited with attacking eight people within ten weeks, five of whom were killed.