"Other remains were found on a sprawling farm in suburban Philadelphia but they still needed to be identified," authorities said of the search in New Hope, according to the AP.
ORIGINAL STORY: Pennsylvania authorities and the FBI are searching for four young men between the ages of 19 and 22 who vanished within days of each other last week, one on Wednesday and three on Friday.
During a Monday afternoon news conference, Bucks County District Attorney Matthew Weintraub said investigators are running down leads in the disappearances and “are making great progress” as they search a large area of farmland about 30 miles outside Philadelphia.
"We're not going to rest until we get through every inch of that property," Weintraub said, according to The Associated Press.
The missing men are identified as 19-year-old Dean Finocchiaro, 19-year-old Jimi Tar Patrick, 21-year-old Tom Meo and 22-year-old Mark Sturgis.
Finocchiaro, Meo and Sturgis all knew each other, the AP reported, and news outlets have reported that cars belonging to two of the men have been located.
While authorities said they're making progress in the search, Weintraub also said foul play is suspected in the disappearances.
"I don't know how this is going to end up, unfortunately, but I am confident that we are going to get to the bottom of this," Weintraub said.
Authorities have arrested the son of the property owner where the search is underway on an unrelated gun charge, WTXF reported, and are holding him as they try and figure out the relationships among the men.