The active search involves state police helicopters, police dogs, and officers from Solebury, Newtown Township, Middletown and Buckingham as well as Bucks County detectives and the county district attorney's office.
The four men reported missing are Mark Sturgis, 22, of Pennsburg; Tom Meo, 21, of Plumstead; Dean Finocchiaro, 18, of Middletown; and Jimi Tar Patrick, late teens, of Newtown Township, authorities say.
"Obviously right now we're treating this as a criminal investigation but nobody is in custody and the search is ongoing," Bucks County First Assistant District Attorney Gregg D. Shore said Sunday night. He said the investigation into the missing men led the authorities to search the Solebury property near Meetinghouse and Aquetong roads.
Sturgis' parents, Mark Potash and Aimee King, said their son, who is friends with Meo, went missing on Friday and that they had filed several missing person reports over the weekend.
Potash, of Pennsburg, called the last few days "a nightmare."
It's unclear how the four men are connected beyond the friendship link with Meo reported by Sturgis' parents. The parents say they were led to Solebury after receiving reports from police and social media that Sturgis' vehicle was found in the parking lot of the Peddler's Village shopping complex and another vehicle driven by one of the other men was found in the area where police are searching.