Unsettling new information has been released about Joseph DeAngelo, the suspected Golden State Killer, who has been linked to at least 12 murders and dozens of rapes decades ago in California.

The New York Daily News reports that Paul Holes, the investigator who initially cracked the case and tied DeAngelo to the crimes, revealed a stunning detail about the investigation in a recent podcast series called “My Favorite Murder.”

Holes told podcast hosts Karen Kilgariff and Georgia Hardstark that the killer would sometimes restrain female victims and put them in front of a television with a towel draped over the screen “so he would have this glow, so he could see her.”

Here’s what Holes said about the first time he entered DeAngelo’s house earlier this year: “(I) walk into DeAngelo’s room, and he has a computer there, and he’s got a towel over the monitor,” Holes said in the podcast.

Holes said he asked himself whether the towel was merely a dust cover or if DeAngelo was attempting to reminisce from his tortured crime spree.

“Is he pulling out any of those souvenirs and replicating the glowing environment from back in the 1970s?” Holes asked.

Authorities say the Golden State Killer, who also has been referred to as the East Area Rapist, stole jewelry from his victims as trophies.

Police descended on DeAngelo’s suburban Sacramento home in April after he was identified with the help of an online genealogy service.

Prosecutors have charged DeAngelo, 72, with 12 counts of murder. Investigators also believe he raped upwards of 50 women and broke into at least 150 homes between the 1970s and 1980s.

DeAngelo has thus far kept quiet and has refused to cooperate in the investigation, according to Holes.

“I watched seven hours-worth of the interviews, and I just don’t see him talking,” Holes told the podcast. “He’s a psychological sadist.”

[Feature image: Joseph DeAngelo/Rich Pedroncell for Associated Press]