Patrick was last seen by his family on July 5 and the others have been missing since July 7.
Federal Bureau of Investigation officers were seen continuing to search the farm on Thursday evening. Not far away, another body was in a grave.
It's unclear if DiNardo planned to kill them ahead of time. Authorities are expected to release additional information on the case Friday morning.
On Thursday, Cosmo DiNardo confessed to participation in what he said were the murders of four young men who went missing last week: Dean A. Finocchiaro, 19; Mark Sturgis, 22; Tom Meo, 21; and Jimi Tar Patrick, 19. Investigators continue to dig and sift through dirt at the Solebury Township farm where the bodies were discovered. They found the remains of the three bodies Thursday and by the evening had gotten Dinardo to confess.
Dinardo, who was arrested for theft on Wednesday, confessed to his involvement in the killings the next day, his attorney Paul Lang said.
"We have so much more to do to bring justice in this case", Bucks County District Attorney Matthew Weintraub told reporters Friday.
"I don't understand the science behind it, but those dogs could smell these poor boys 12-1/2 feet below the ground", Weintraub said.
"I mean, I know the kid", Cosmo answered. "I'd like to think that he wanted to help us get these boys home".
Prosecutors confirmed DiNardo will not face the death penalty after agreeing to plead guilty to four first-degree murder counts.
Dinardo and Kratz are cousins, the criminal complaint states.
DiNardo, 20, pinned one of the deaths on his cousin, who was charged on Friday, although the cousin told police that DiNardo shot all four of the victims. DiNardo then continued to shoot at his body after he had died, The Daily Mail said. Investigators later determined that Kratz had sold the pieces for $345 at a resale shop on Cottman Avenue.
Dinardo, whose parents own the Solebury Township farm being searched, was already in custody after being accused of stealing and trying to sell a vehicle belonging to one of the missing men. "They walked to a remote part of the property, where DiNardo said he fatally shot Patrick with a.22-caliber rifle", according to prosecutors.
DiNardo told investigators he agreed to sell a quarter-pound of marijuana to Finocchiaro for about $700 on July 7.
DiNardo's lawyer says his client is remorseful. When they made it to the barn, Kratz shot Finocchario in the head.
Patrick only had $800, so DiNardo told him he had a shotgun he could sell him for that amount instead, according to the court documents. That only added to the speculation and rumors before DiNardo's confession.
In a separate statement, Kratz largely corroborated DiNardo's story, saying Meo died after DiNardo "basically crushes him" with the backhoe. Then, according to a police affidavit, he placed the Finocchiaro's body in a metal tank he referred to as the "pig roaster", doused the corpse in gasoline, and lit it ablaze.
"There was an attempt to burn the bodies, to obliterate them, but I don't believe that was successful", Weintraub said.
Dinardo told investigators that Meo and Sturgis followed him to the Solebury property in Meo's Nissan Maxima, the documents say.
He was arrested on a gun charge, which was later dropped.
Earlier this year, authorities charged DiNardo with possessing a firearm despite an involuntary mental health commitment.
NBC10 has been tracking the mystery of four missing men in Bucks County, Pennsylvania.
He was back in custody Wednesday for allegedly trying to sell Meo's auto, prosecutors said. He is being held at the Bucks County Jail on $5 million bail. Kratz was arrested later the same day, authorities said.