PHILADELPHIA (AP) — The search for four missing young Pennsylvania men feared to be the victims of foul play is set to continue Tuesday, a day after authorities arrested a man linked to a property that has become the focus of the investigation.

Officials said they were chasing "incredibly hot" leads as they spent much of Monday scouring a large swath of farmland in Solebury Township, about 30 miles (48 kilometers) north of Philadelphia, in their search for 22-year-old Mark Sturgis, 21-year-old Tom Meo, 19-year-old Dean Finocchiaro, and 19-year-old Jimi Tar Patrick. One of the men disappeared on Wednesday and three others on Friday.

"We're not going to rest until we get through every inch of that property," Bucks County District Attorney Matthew Weintraub said at a Monday afternoon news conference.

Hours after Weintraub's briefing, authorities arrested Cosmo DiNardo, whose family owns the sprawling farmland, on an unrelated gun charge. According to a police affidavit obtained by the Bucks County Courier Times, the 20-year-old Bensalem man was accused of possessing a shotgun and ammunition in February despite a history of mental illness that includes a voluntary commitment. DiNardo was ordered held on $1 million bail. His lawyer and parents could not immediately be reached for comment. Authorities have not called him a suspect in the men's disappearance.

Weintraub said it remains unclear what relationship the missing men have with each other. But Sturgis' father, Mark Potash, told

The Associated Press that his son and Meo are longtime friends who work in construction for him. He said Finocchiaro is a mutual friend of theirs.

The FBI, Pennsylvania state police and five local law enforcement agencies have joined the case, Weintraub said, describing the investigation as "all hands on deck."