NEW HOPE, Pa. >> The body of one of four missing young men was found along with other human remains inside a 12-foot-deep common grave on a Pennsylvania farm linked to a 20-year-old man taken into custody today.

Bucks County District Attorney Matthew Weintraub pledged at a midnight news conference to “bring each and every one of these lost boys home to their families.” Cadaver dogs had led them to the spot on the 90-acre farm where the FBI has spent days digging up the grave and sifting through the dirt for evidence. The other remains still need to be identified. The cause of deaths of those found in the grave has not yet been announced.

“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.

Cosmo DiNardo was being held on $5 million cash bail after he was charged today with trying to sell another victim’s car after he disappeared. The car was found on the DiNardo family property.

The body identified early Thursday was that of 19-year-old Dean Finocchiaro. The missing men are 22-year-old Mark Sturgis, 21-year-old Tom Meo and 19-year-old Jimi Tar Patrick. Patrick, who was a year behind DiNardo at a Catholic high school for boys, was last seen today, while the other three vanished two days later.

DiNardo also had been arrested Monday and held on $1 million bail on an old gun charge, before his father paid $100,000 to bail him out Tuesday. The charge stems from accusations that DiNardo was caught with a shotgun and ammunition in February despite a prior mental health commitment.

The back-to-back arrests bought investigators time as they scoured the farm and other spots across the county for clues to the men’s disappearance, Weintraub said. He hoped the higher bail would hold him even longer, but acknowledged it might not.

DiNardo’s parents, Antonio and Sandra DiNardo, own the farm in upper Bucks County, a bucolic area with rolling hillsides, new housing developments and historic sites. They also own a nearby farm parcel that was also searched and a concrete company near their home in Bensalem, closer to Philadelphia.

An attorney representing the couple issued a statement earlier today saying they sympathize with the families of the missing men and are cooperating “in every way possible with the investigation.”

The FBI had been using heavy equipment to dig a deep ditch on the farm property, and then sifting through each bucket of dirt by hand.

At least some of the missing men are friends, but it’s unclear how well they knew DiNardo, if at all.

In the February gun charge he still faces, DiNardo is accused of illegally being in possession of a shotgun and ammunition because of a previous involuntary commitment to a mental health institution. An affidavit in that case said he is “known to be suffering from mental illness.”

His social media posts suggest an avid interest in hunting, fishing and Air Jordan sneakers, which he appeared to sell online. He had enrolled in a nearby college at one point as a commuter student, with hopes of studying abroad in Italy, according to an article on the college website. He had a few other brushes with the law since turning 18 over traffic violations and other minor infractions.