Accused Pennsylvania Killer Cosmo DiNardo Told Cops He's Killed Before: Report

The man accused in the slayings of four men who vanished in suburban Pennsylvania reportedly claims they're not his only victims.

The Pennsylvania man accused in the slayings of four young men who disappeared within days of each other claims he's killed before, according to reports.

Cosmo DiNardo confessed last week to the murders of Jimi Taro Patrick, 19; Dean Finocchiaro, 19; Mark Sturgis, 22, and Tom Meo, 21. 

Read: Second Person of Interest Arrested in Case of Slain Pennsylvania Men: Report

Now, police sources have revealed the 20-year-old construction heir told cops he killed two others in Philadelphia when he was just 15, according to The New York Times.

DiNardo's Bucks County attorney declined to comments on those reports Monday.

However, police are reportedly attempting to determine whether there is a link between the claims and any unsolved cases in Philadelphia.

A spokesperson with the Bucks County District Attorney said the office is vetting all statements made by DiNardo in his Thursday confession.

The 20-year-old and his cousin, Sean Kratz, also 20, were charged with murder on Friday. No bail was set for either.

Kratz allegedly used heavy construction equipment to dig a 12-foot grave in which the victims were buried. The grave site is located on a $5 million farm owned by DiNardo's parents.

"There was an attempt to burn the bodies, to deface them, to obliterate them, but I don’t believe that was successful," Bucks County District Attorney Matthew Weintraub said in a press conference Friday. "We were able to secure the two weapons that we allege were used in these four murders."

Weintraub confirmed that the remains of all four men have been found.

Kratz was reportedly arrested after his cousin told cops he'd been involved.

One source reportedly says the murders happened because DiNardo felt "cheated" after several drug deals.

In his Friday news conference and in documents detailing the killings, Weintraub made no mention of murders beyond the four young men DiNardo says he and his cousin killed in the field in early July.

Weintraub's spokesperson said Monday that his office was not the source of information to The New York Times and will not talk about this issue.

Despite the startling reports and the nature of the crimes, DiNardo feels "deep remorse" and is "very emotional," said Paul Lang, one of his lawyers.

Read: Person of Interest Arrested in Case of 4 Missing Pennsylvania Men

In exchange for his full confession, DiNardo will be spared the death penalty, Lang said.

A motive for the killings was not released. DiNardo has a history of mental illness and has previously been held against his will in a psychiatric facility, according to a probable cause affidavit filed by Bucks County police. 

Watch: Police Searching for 4 Young Men Who Went Missing Within Days of Each Other