ST. LOUIS • A West Virginia man who sexually abused children for four decades was sentenced in federal court here Thursday to 160 years in prison.

Jack E. Gravenmier, 80, wasn’t stopped until a boy in Missouri told his mother what happened, and that he was still in contact with Gravenmier. She told police, and they took over the teen’s correspondence with Gravenmier.

During those communications, Gravenmier talked about his collection of child porn and boasted of the other minors with whom he’d had sex, the charging documents allege. Gravenmier sent a detective child pornography, including images he had taken of his other victims.

He had reserved a room at the Troy, Mo., Super 8 motel and had promised to bring two memory cards with images and videos of child pornography, $100 and sex-related materials, court documents say.

He was arrested in St. Louis last year while on his way to meet the teen.

At the sentencing hearing, Assistant U.S. Attorney Rob Livergood said Gravenmier had been abusing children since the 1970s, when he handed out candy to kids in hopes of having sex with them. In some cases, he used threats or intimidation to scare the children into submitting, Livergood said.

Gravenmier was investigated in 2001, but he didn’t stop abusing children, Livergood said. It was not clear what happened in that investigation.

Gravenmier’s former son-in-law Larry Mundy told the Post-Dispatch that he found child pornography in a darkroom in Gravenmier’s house in the 1970s and reported it to authorities in Charleston, W.Va., but that the police cleared him. West Virginia authorities contacted by a reporter said they could find no records from that period.

At Thursday’s sentencing, relatives of a handful of victims told U.S. District Judge John Ross about the pain Gravenmier left in his wake. “This is one of the worst, most egregious cases I’ve ever seen,” Ross said. “Your conduct is simply despicable.”

One victim wrote a letter in which she said she worried that others would see the pictures Gravenmier had taken of her.

“You destroyed me,” another wrote in a letter to him. “You took away my happiness.”

“There’s a lot of carnage sitting in this courtroom today,” said the father of one victim. “A lot of destroyed lives.”

Gravenmier pleaded guilty in January to two counts of production of child pornography, one count of attempting to persuade a minor to engage in sexual activity, one count of travel with the intent to engage in illicit sexual conduct, two counts of producing child porn and two counts of possession of child porn for crimes in Missouri and West Virginia.

As part of the case, the retired chemical engineer will have to forfeit two vehicles and his home in West Virginia. The vehicles have already been sold. The proceeds will go towards paying $160,000 in restitution to five victims in Missouri and two other states.

Robert Patrick covers federal courts and federal law enforcement for the Post-Dispatch. Follow him on Twitter: @rxpatrick.

Robert Patrick is a reporter for the St. Louis Post-Dispatch.