Veteran Army medics Preston and Billy both claim they were drugged and raped by serial killer Jeffrey Dahmer while serving with him in the 68th Armored Regiment of the U.S. Army at Baumholder, Germany. Billy, who was Dahmer’s roommate in 1980, says he was physically brutalized and psychologically tortured over and over. Preston, who first met the serial killer in 1979, says he repressed the memory of a single attack by Dahmer for over 30 years. Now both men say they believe Dahmer killed while stationed in Germany.

“He had so much blood on him that, when he took his clothes off, he had to peel his clothes off,” says Billy about an incident after Dahmer came back to the base after a weekend away. Hear more in the video above.

Part one of this three-part Dr. Phil, “In The Presence of Evil: Face to Face with Jeffrey Dahmer,” airs Tuesday. Then, tune in Wednesday for part two, “Raising Evil: The Interview with Jeffrey Dahmer's Father," as Lionel Dahmer talks to Dr. Phil about the traumatic event he suggests triggered his son to kill for the very first time.

Check your local listing for airtimes.

WATCH: Jeffrey Dahmer’s Army Roommate Claims The Serial Killer Drugged, Raped, Psychologically Terrorized Him

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