Haunted by his abusive past, raging at God over the death of his daughter, killer Charles Roberts laid intricate plans to make innocent Amish schoolgirls pay for his torment.
"He was deeply troubled ... and I think it was just a matter of time before he did something," Pennsylvania State Police Commissioner Jeffrey Miller said on Tuesday.
Roberts, 32, who killed five Amish girls aged seven to 13 in his murder spree on Monday, took flex cuffs, a personal lubricant, bolts, latches and wooden planks mea-suring 0.6m by 1.8m, 600 rounds of ammunition, a hammer, tape, wire and other tools to the yellow, wooden, one-room schoolhouse.
The shameful inventory can have had only one purpose, said police, who sifted rambling suicide notes and interviewed the killer's traumatized wife, family and friends.
Roberts meant to molest his victims, even as he was wracked by nightmares of what he claimed was his sexual abuse of two young family members, which he confessed to his wife in a cellphone call moments before the killings, they said.
"The KY jelly has no exact reason other than the potential for a sexual assault," said Miller.
"The two by sixes [planks] had eye-bolts connected close together, but there were two sets about 10 inches apart, so he had 10 victims, and somebody could be restrained in a way with their hands or their back," he said. "It's very possible that he intended to victimize these children in many ways prior to executing them and killing himself."
In what he called a "horrendous" crime scene, Miller said his men had discovered dead and injured girls bound by their feet, when they stormed the school, and had to cut them out. Police said there was every indication he was targeting the girls and not the Amish community specifically.
Though there was no evidence Roberts assaulted the girls before he was panicked into setting off a hail of gunfire by approaching police, the sordid revelations on Tuesday deepened the agony of the sleepy Amish community.
The Amish, who have quietly brought their 400-year-old community habits into the 21st century, have drawn in on themselves and are grieving as an extended family, police said.
Non-Amish neighbors were simply shellshocked.
On the morning of the killings, which started after Roberts clocked off nightshift, and dropped his kids at the school bus stop, his wife Mary had been at a local prayer group, said Pastor's wife Kristine Hileman.
"She was the leader of the prayer group devoted to children, it was a Godly moment," Hileman told reporters.
Mary Roberts later wrote in a statement, "the man who did this today was not the man we knew."
She told police that her late husband was still traumatized by the loss of infant daughter Elise, who lived for just 20 minutes after birth in 1997.
"Roberts was angry with God for taking [her] as outlined in the suicide note," Miller said.
The Amish live a simple existence to preserve their austere, pacifist principles.