THE notorious murderer known as the Happy Face Killer has claimed that Gilgo Beach serial killer suspect Rex Heuermann has written to him from jail, making the comments in a chilling police interview caught on camera.

The Happy Face Killer, whose real name is Keith Jesperson, 68, was infamous for a string of homicides in the 1990s.

He got the name after sending detailed letters about the killings to the media after committing the crimes, signing with a smiley-face at the bottom of the notes, per Yahoo! News.

After seven murders, Jesperson was arrested as a suspect in connection to the crimes in 1995.

Jesperson, a semi-truck driver, also told police in 1996 that he’d killed an eighth victim two years prior that investigators hadn’t discovered yet.

He explained that the woman’s name was either Susan or Suzette, and he hid her body off Interstate 10 in Florida in August 1994.

A worker discovered the body one month later, but it wasn’t until Tuesday that the Okaloosa Sheriff’s Office was able to identify the body as that of then 34-year-old, Suzanne Kjellenberg.

Sheriff Eric Aden said that Jesperson was a prime suspect since 1996, given his recount of the killing and the similarities in the information and evidence provided, but they had trouble identifying the body.

“We had him as a suspect early on — just didn’t have an identity for our victim,” Aden noted.

They then officially charged Jesperson with the murder.

“Thanks to the tireless efforts of so many over so long, the remains of Suzanne Kjellenberg, the final unidentified victim of Jesperson’s cross-country murder sprees, can finally leave the Medical Examiner’s Office, and return home.”

Jesperson also had an interview from behind bars at Oregon State Penitentiary with investigators in September that was recorded on video, where he explained the killing of Kjellenberg further.

The Happy Face Killer said he met the young woman at a rest stop, and she allegedly told him she needed a ride to Lake Tahoe.

Jesperson claimed that he told her he didn’t know where she was headed, but they went along together anyway, sharing a meal and traveling through Cairo, Georgia, about 34 miles north of Tallahassee, Florida.

Read Related Also: Special Edition Beer with Trump’s Mugshot Sees ‘Record-Breaking’ Sales

The pair stopped at a rest stop over the border, and he said he sat next to Kjellenberg on a mattress in the driver’s lounge when she allegedly started screaming.

“She just sat up and started screaming,” Jesperson claimed while speaking to authorities in the interview.

“I was like, ‘Shut up!’ and the more I told her to ‘shut up,’ the more she screamed.”

He continued: “And I don’t need that, because I wasn’t supposed to have people in my truck anyway . . . so I just killed her.”

The Happy Face Killer added that he then zip-tied her body and dumped it along Interstate 10.

Although the admission from Jesperson and the details about the eighth murder were shocking, he also made a chilling note of a letter he received in recent years from none other than Gilgo Beach Murders suspect, Rex Heuermann.

Heuermann was identified as a suspect in the killings long after police discovered at least 10 bodies throughout 2010 and 2011 along the Long Island, New York, beach highway.

The Manhattan-based architect pleaded not guilty to three counts of first-degree murder and three counts of second-degree murder in the Gilgo Beach deaths case.

Jesperson explained in the clip that he would write letters to other suspected serial killers after they were arrested and encouraged them to plead guilty and be honest.

He added that the only reason they were sought out by police in the first place was that they seemingly had enough evidence to prove they committed the crimes.

That’s when he brought up Heuermann.

“I recently got a letter from Rex Heuermann from the Long Island serial killer, and I told him the same thing,” Jesperson could be heard telling police.

“And he wrote me back and said, ‘I’ll take it under advisement.'”

At a court hearing on September 27, Heuermann could be seen seemingly emotionless as a judge gave a ruling on 200 guns that were found at his residence.

His next court hearing is set for November 15, per ABC News.