A 20-year-old man was arrested Wednesday on charges of trying to sell a car belonging to one of four missing Pennsylvania men, and a prosecutor said he believed there would soon be “finality” in the search for the apparent victims of foul play.

Authorities got perhaps their biggest break with the discovery Sunday of one of the men’s cars. In a subsequent search of Tom Meo’s vehicle, investigators found his diabetes medicine, which his family said he never went anywhere without.

A judge ordered Cosmo DiNardo, whose family owns the farmland where a massive search has been underway since Sunday, held on $5 million cash bail on the stolen vehicle charges.

DiNardo was described as a person of interest in the investigation after he was first arrested Monday on an unrelated gun charge. His father put up $100,000 to bail him out Tuesday. District Attorney Matthew Weintraub said he wanted a higher bond to make sure he remained behind bars because he posed an even greater flight risk. DiNardo was described as a danger to the community.

The prosecutor said important evidence had been found both at the farm about 30 miles (48 kilometers) north of Philadelphia and other properties, but no human remains.

“The search at the scene is really intensifying,” Weintraub said late Wednesday upon announcing the arrest. “I’m very encouraged ... that we’re going to get some finality in this just prolonged ordeal.”

Besides Meo, 21, the other missing men are Mark Sturgis, 22, and Dean Finocchiaro and Jimi Tar Patrick, both 19. Patrick disappeared last Wednesday; the other three vanished Friday. At least three of them were friends.

According to a police affidavit, police found Meo’s car Sunday on a DiNardo family property in Solebury, the town where the farm is also located. They said the keys and a title were hanging up in a garage. A witness said DiNardo offered to sell him the car on Saturday.

On the last night Meo and Sturgis were seen, a police license plate scanner picked up DiNardo’s truck and Meo’s car driving just seconds apart. The location was within a couple of miles from where Meo’s car was found and where Sturgis’ vehicle was discovered, a short distance away.

An attorney for DiNardo’s parents, Antonio and Sandra DiNardo, issued a statement Wednesday saying the couple sympathize with the families of the missing men and are cooperating “in every way possible with the investigation.”

The DiNardo farm alone covers 90 acres, much of it cornfields. They also own other nearby farm parcels, along with concrete and construction businesses based in Bensalem, about 20 miles (32 kilometers) away, where the son was arrested at the family home.

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

At a morning briefing, Weintraub said police would “continue digging and searching that property until we’re satisfied that they are not there.”

“This is just really, really rough on everybody involved because of the heat, the magnitude, the scope — and the stakes are incredibly high, life and death,” he said.

At least some of the missing men are friends, but it’s unclear how well they knew DiNardo, if at all. Online records suggest he attended the same Catholic high school as Patrick but was a year ahead.

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.