Illinois ? Just hours before a man was to attend a memorial service for his wife and three young children, authorities arrested him at a Missouri funeral home on charges of gunning down his family in their sport utility vehicle.

Police initially said Christopher Vaughn, 32, was not a suspect in the killings that were discovered June 14 after Vaughn flagged down a motorist on a service road in Channahon, about 40 miles southwest of Chicago.

Vaughn, who works as a computer forensic adviser, had been shot in the thigh. His wife, Kimberly, 34, was shot once, while each their children – Abigayle, 12; Cassandra, 11; and Blake, 8 – were shot twice. His handgun was found at the scene, authorities said.

Prosecutor James Glasgow, who declined to discuss possible motives, said Vaughn was charged with two murder counts per victim. One set of counts alleges he shot with intent to kill and the other alleges he shot knowing that it was likely to cause death or great bodily harm.