(Newser) – A surprise visit to a friend's home with his young son on Friday ended up being a deadly decision for Justin Stanfield Thomas. The 35-year-old Army Special Forces veteran and former Green Beret was shot dead by his 4-year-old, who police say found an unsecured gun in the living room of the home in Prescott Valley, Ariz. A neighbor tells ABC15 that the homeowner was also a vet and that Thomas had formerly lived in the home, but moved out in the fall after learning his girlfriend was pregnant; that child is now 2 months old. Police believe the homeowner wasn't expecting the visit, which may explain why the gun was present.

A police department rep says the investigation into the accident will continue this week, with police looking to determine how much time passed between their arrival and the shooting. Once they establish how long the homeowner may have had to deal with the gun, prosecutors will decide whether to charge him with criminal negligence, reports the Arizona Republic. According to the neighbor, it wasn't very long: "Apparently when Justin and his little boy showed up, within minutes, the little boy found the gun and said, 'hey, daddy, what's this?' and it went off," he tells AZFamily.com. (Read more shooting stories.)

