What led Joseph Aldridge to gun down seven people in a southern Missouri hamlet remained uncertain on Saturday, though authorities speculated that the death of the gunman's mother from cancer could have triggered the rampage.
Aldridge, 36, embarked on a shooting spree late on Thursday in the rural community of Tyrone, going door to door in the wintry night, killing four relatives and three neighbors, and wounding another, before fatally shooting himself, police said.
The massacre unfolded shortly after Aldridge's mother, 74-year-old Alice Aldridge, died from complications of metastatic lung cancer. Texas County Coroner Tom Whittaker said Saturday that an autopsy revealed the fatal condition. She may have been dead for at least 24 hours when her son began his rampage, Whittaker said.
"Why it went to this extent, we don't know and I don't know that we ever will," Whittaker said.
Most of the victims were found in their bedrooms, according to Whittaker.
At least two children in two separate homes escaped injury while their parents were murdered, according to the Texas County Sheriff's Office.
One of the children, a teenage girl, fled to a neighbor's house where she called police. The girl's parents, Garold Aldridge, 52, and his wife Julie Aldridge, 47, were found dead in their home, the sheriff's office said.
Harold Aldridge, 50, and his wife Janell Aldridge, 48, were found dead in a separate residence. Harold and Garold were cousins of Joseph Aldridge, police said.
The other three killed were members of prominent family that ran several businesses in the region, including a cabinet making shop, a cattle ranch and an auto dealership.
Authorities said they were Carey Shriver, 46, and his wife Valirea Shriver, 44, and Carey's father Darrell Shriver, 68. Darrell's wife Martha, 67, was wounded but survived and is recovering, Texas County Sheriff James Sigman said in a statement issued Saturday.
Carey and Valirea's 13-year-old son was asleep in his room when his parents were killed and was discovered safe by police, according to local media reports.
There was no sign of forced entry in any of the houses where the shootings occurred, said Sigman, adding that the killings had shattered a sense of safety in the town.
"Start locking your doors. The world is changing. You got to be safe," he said.
A review of court records shows that Aldridge had a history of using drugs. In 2008, he was sentenced to 21 months in federal prison for possessing a handgun while using marijuana, and was ordered to undergo mental health and substance abuse counseling, court records show.
Tyrone, an incorporated community with about 50 residents, is about 160 miles southwest of St. Louis, near the Mark Twain National Forest, in an area that attracts hunters, campers, and river rafters. About 10 miles down the road in the county seat of Houston, Missouri, Houston Mayor Don Tottingham said memorial plans for the victims will likely be coming together in the next two to three days. The community continues to search for an explanation for Aldridge's shooting spree, he said. "The community was certainly stunned by the murders but is trying to come together to deal with the grief of the family members and the many friends and neighbors in the community," Tottingham said. "Please keep the community in your prayers."
