Elmer Wayne Henley Jr. was a 15-year-old gas station worker when he became an accomplice to the “Candy Man” serial killer.

Now 69, Henley is serving a life sentence for his part in helping Texas murderer Dean Corll lure young victims to be tortured and killed during the ‘70s. Henley is speaking out in a new Investigation Discovery (ID) true-crime documentary, “The Serial Killer’s Apprentice.”

In the film, Henley has candid conversations with renowned forensic psychologist Katherine Ramsland, who studied his case. According to the network, this is the first time in decades Henley is speaking out in great detail about the killings.

Elmer Wayne Henley Jr. covers his face after his arrest. (Investigation Discovery)

“Wayne brought a girl over with another kid,” said Ramsland. “Corll had bound all of them and said he was going to kill them all. Wayne persuaded him to let him go and said he would help. … When Corll laid the gun down and went after the boy, the girl said something to Wayne like, “Aren’t you going to do something about this?’”

It was Corll who taught Henley how to shoot. And when Corll came charging at him, Henley killed the 33-year-old with his gun.  

Elmer Wayne Henley Jr. leads law enforcement agents along a grassy dune on a beach on High Island, Texas, as they search for victims. (Getty Images)

Later that day, a shaken Henley led police to the bodies of the victims. Over three days, investigators found 16 bodies wrapped in plastic or sheets and buried in a mass grave. Most of the bodies were badly decomposed, and their identities were obscured by time and the elements, The Associated Press reported. The outlet noted that the conditions of the bodies showed traces of suffering.

Over the years, investigators were able to identify known victims.

Elmer Wayne Henley Jr. covers his face as he talks to reporters. (Getty Images)

Henley quickly admitted direct involvement in six of the killings and said he struggled with his actions but feared being killed by Corll.

Henley and Brooks received life sentences. Brooks died in 2020 of complications from COVID-19.

Elmer Wayne Henley Jr. waits in an officer’s car while bodies were being recovered. Henley told police he fatally shot Dean Corll on Aug. 8, 1973, after hours of drinking and glue sniffing. He is serving a life sentence. (David Nance/Houston Chronicle via Getty Images)

Ramsland said that, based on her numerous conversations and letters with Henley, she assessed him as both a victim and a perpetrator. It’s something that needs to be studied more because “we’re going to see more of it,” she argued.

Mass murder suspects Elmer Wayne Henley Jr. and David Brooks at High Island Beach, where authorities were searching for bodies. (Jerry Click/Houston Chronicle via Getty Images)

“I don’t put [a person like this] on any level like the victims who were tortured and killed,” Ramsland stressed. “By no means is he that kind of victim. But victims come in all varieties, and I don’t think you can deny that.”

Ramsland believes Henley continues to be haunted by his actions.

A newspaper headline gives details about the murders committed by electrician Dean Corll, who, along with younger accomplices David Brooks and Elmer Wayne Henley Jr., is believed to have killed at least 27 boys. Corll was killed by Henley during an altercation, after which Henley confessed to the police about his role in the murders of the teenage boys and gave evidence about where the bodies could be found. (Getty Images)

“He wanted to be a minister,” she said. “He doesn’t know what to think of himself.”

“The Serial Killer’s Apprentice” premieres Aug. 17 at 9 p.m. The Associated Press contributed to this report.