The prosecutor said he was hopeful more will be able to be identified.
On Wednesday afternoon, Weintraub said investigators had found a auto allegedly stolen from one of the missing men and charged DiNardo with theft.
He will plead guilty to four counts of first-degree murder, said defense lawyer Paul Lang. But the prosecutor continued to stop short of calling him a suspect.
The discovery on the sprawling Bucks County farm Wednesday came five days after an intensive investigation on the property involving at least five municipal police departments, state police and the FBI.
Kratz, then 19, of Susquehanna Road in Ambler, was arrested on charges of retail theft, receiving stolen property, possession of an instrument of crime and possession of a controlled substance on December 9 at Macy's in the Willow Grove Park Mall.
The prosecutor has dribbled out details of the investigation at twice-daily briefing near where the remains were found.More news: GOP operative who hunted for Hillary Clinton's emails killed himself
The mysterious case of the missing men - all between the ages of 19 and 22 - has transfixed this region since all four vanished last week. Weintraub's office would not confirm or deny media reports that Dinardo had implicated a co-conspirator and that someone in Philadelphia was taken into custody late Thursday night. When the three men arrived to the property, DiNardo says Kratz shot Finocchiaro in the head, and that DiNardo shot him again while he was on the ground. Make no mistake about it.
Weintraub told a news conference on Friday that he did not know the motive behind the murders.
A day after a man here confessed to his role in killing four Pennsylvania men whose disappearances set off an intensive search, questions remained Friday about what unfolded in the rolling hills north of Philadelphia.
Authorities had charged DiNardo earlier this year with having a gun despite an involuntary mental health commitment.
DiNardo was seen exiting the Bucks County Courthouse on Thursday evening saying, "I'm sorry".
Meo's 1996 Nissan Maxima, with the title inside, was found Sunday around 4 a.m. ET, on a nearby property owned by the DiNardos, Weintraub said in a news release. They also own a concrete company near their home in Bensalem, closer to Philadelphia. "They are cooperating in every way possible with the investigation being conducted by law enforcement".More news: US Drone Strike Obliterates Islamic State's Afghan Leader
On Wednesday, investigators found three bodies in a common grave under an oil tank on the farm.
Whether the other men knew each other isn't known, though there are "indications that some or all of the men knew one another", Weintraub's office said.
Fire and rescue crews on Thursday were using plywood to help shore up the deep grave as investigators worked inside under intense heat and choking dust.
Weintraub said there was an attempt to burn the bodies, but investigators do not believe it was successful.
Sean Kratz is charged in the deaths of Dean Finocchiaro, 19, Thomas Meo, 21, and Mark Sturgis, 22. Patrick disappeared on July 5 and the three others went missing two days later.More news: Atwood Oceanics, Inc. (NYSE:ATW) Stake Boosted by Arizona State Retirement System
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