An Army Special Forces veteran who served in the Iraq War was accidentally shot and killed by his 4-year-old son in northern Arizona, police said.

Justin Stanfield Thomas took his son to visit a friend in Prescott Valley when the boy found a gun in the living room and accidentally shot his father in the chest, azfamily.com reported.

“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,” said Jeremy Hartt, a neighbor and friend. “He didn’t know what was going on; he was just a happy little boy.”

Thomas was rushed to a nearby hospital where he was pronounced dead, KSAZ-TV reported.

Police say the visit might have been unexpected, explaining why the gun was left out.

The child was taken to the police station for questioning, but didn’t appear to realize what he had done, according to the station. He was released into his mother’s custody.

“At this point there is no indication of any foul play,” Prescott Valley Police spokesman Brandon Bonney told KSAZ. “Once investigators go through the residence … and fully process it they’ll look and see if there’s any negligence involved … but it’s something we won’t know for some time now.”