Another man has been arrested in the deaths of four Bucks County men, culminating a weeklong investigation into their mysterious disappearances.

Cousins Cosmo DiNardo and Sean Kratz, both 20, are charged in the deaths of Dean Finocchiaro, 19, of Middletown; Thomas Meo, 21, of Plumstead; and Mark Sturgis, 22, of Pennsburg. DiNardo also faces charges in the slaying of killing Jimi Tar Patrick, 19, of Newtown. The two also face charges for abuse of a corpse, robbery and criminal conspiracy.

DiNardo, who had been in police custody as a "person of interest," confessed to the slayings Thursday. Kratz was arrested Friday in Northeast Philadelphia.

Sworn statements by the Kratz of Philadelphia and DiNardo of Bensalem describe meeting the other men to sell them marijuana, taking them to the DiNardo family property in Solebury, then shooting them.

Asked about a motive during a Friday news conference, the Bucks County district attorney was at a loss.

"I don't know that. I'm not really sure if we could ever answer that question," said District Attorney Matthew Weintraub.

According to an affidavit, DiNardo initially told police he'd been fishing in the Washington Crossing area on July 7, when three of the four men disappeared. DiNardo later told police that he'd been lying.

On July 5, DiNardo agreed to sell Patrick four pounds of marijuana for $8,000, according to his sworn statements. DiNardo said Patrick brought only $800 with him, so DiNardo offered to sell him a shotgun instead. After the exchange on the farm owned by the DiNardo family, DiNardo shot Patrick.

Two days later, DiNardo — this time with Kratz — arranged to sell Dean Finocchiaro a quarter pound of pot. DiNardo stated the two decided to rob Finocchiaro instead. Kratz and DiNardo each claimed the other killed Finocchiaro.

DiNardo said he had another "deal" arranged for later that evening, July 7, with Tom Meo. Meo and Sturgis arrived at the DiNardo property on York Road intending to buy a pound of marijuana when, according to Kratz, DiNardo started shooting at them.

They put the three bodies in a metal tank, covered them with gasoline and set them on fire.

"There was an attempt to burn the bodies, to obliterate them, to deface them, but I don't believe that was successful," said Weintraub.

The men later used a backhoe to dig the more than 12-foot common grave that investigators painstakingly unearthed this week, according to police documents.

Patrick, the first victim, was buried on another part of the property.

On Thursday afternoon, DiNardo confessed to the killings in order to avoid facing the death penalty, according to his attorney.

"We'd still be looking for Jimi Patrick had we not made this agreement," said Weintraub.

The remains of all four men have been positively identified.

"We've notified all of their loved ones in as peaceful and respectful way as possible, that we now have them in a safe place, so that they can soon be returned home," said Weintraub.

Investigators Friday also searched a property in Ambler, Montgomery County, in connection with the case.