New Jersey’s "Torso Killer" serial murderer pleaded guilty to two more slayings Tuesday, bringing closure to the 1974 cold-case double homicide of a pair of teen girls.

Mary Ann Pryor, 17, and her friend Lorraine Marie Kelly, 16, wanted to buy bathing suits for an upcoming trip to the Jersey Shore on Aug. 9, 1974. So they did what many teenagers did at the time – they hitchhiked to the mall.

The girls left their homes in North Bergen to make a roughly 13-mile trip to the Garden State Plaza mall when they encountered one of the area’s most notorious serial killers – Richard Cottingham.

In this image taken from a New Jersey Courts virtual hearing, Richard Cottingham, center, known as the "Torso Killer," pleads guilty Tuesday, April 27, 2021, to two 1974 murders. (New Jersey Courts via AP)

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The brutal predator gained his nickname, the "Torso Killer," by leaving victims beheaded and dismembered in New Jersey and New York City, sometimes hiding body parts that have never been found.

Cottingham, now 74, has claimed responsibility for killing about 100 people. Investigators have linked him to 11 murders so far but suspect there are more victims.

He left Mary Ann and Lorraine face-down and in the woods near the mall, severely abused and wearing only necklaces that investigators used to help identify the bodies.

In court, Cottingham admitted to kidnapping the girls, then tying them up and raping them both in a motel room. He killed them by drowning them in the bathtub.

Both had been tortured with cigarette burns, according to NJ.com.

Authorities discovered the gruesome scene five days after the girls were reported missing.

Cottingham has been in prison since the 1980s after authorities caught him in the act of a sexual assault and attempted murder when witnesses reported hearing a girl’s screams coming from a motel room. Last year, he also confessed to three killings that happened in the 1960s.

In December 1979, he left two headless victims in a hotel room in New York City’s Times Square, lighting their bodies on fire before fleeing.

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Only one was identified – Deedeh Goodarzi, an immigrant from the Middle East who was working as a prostitute in New York.

Goodarzi had given up a daughter for adoption before her death, and that daughter as an adult tried to find her birth mother, according to NJ.com. When she learned of her gruesome slaying, she sought out Cottingham in prison to demand answers – and the two developed a bizarre friendship.

He reportedly confessed to her that he didn’t care about other people or society and did whatever he wanted. He also told her where he allegedly buried her mother’s head – although investigators haven’t found it.

"I’m doing this for the mothers who lost their daughters and my own mother," Goodarzi’s daughter, Jennifer Weiss, told the outlet. "And for these girls that their lives were ended one night or day by Richard playing God."

Cottingham is already serving life in prison. He is expected to receive two more concurrent life sentences in the 1974 murders in July.

The Associated Press contributed to this report.