Investigators are remaining relatively tight-lipped about the search of the 68-acre property, except to say it could take time to search the farm and farmhouse. The DA stop short of calling DiNardo's father a person of interest.
The farmland being searched is in the town of Solebury, about 30 miles (48 kilometers) north of Philadelphia.
The missing men's photo have begun to appear on digital billboards along highways in the area.
A man, related to the owners of the rural property now being searched, was taken into custody on an unrelated charge on Monday.
Sturgis and Meo are longtime friends who work in construction for Sturgis' father, Mark Potash.
From left to right, Bucks County District Attorney's Office photos show: Dean Finocchiaro, 18, Tom Meo, 21, Jimi Patrick, 19, and Mark Sturgis, 22. Weintraub said he hopes the judge will set a very high bail because DiNardo is "even more of a flight risk".
Speaking to the Trentonian, a neighbor of the DiNardo family in Bensalem described the arrested man as 'pretty nutty.' That neighbor said, 'He used to walk around her in camouflage with a gun hunting squirrels.
Asked about reports from residents that they heard gunshots on that property over the weekend or that there was a bonfire at the DiNardo house, Weintraub said, "I can't comment on that".
District Attorney's Office
According to an affidavit of probable cause filed by prosecutors, DiNardo was "suffering from mental illness" at the time of his February arrest and was involuntarily committed to a mental institution for inpatient treatment. His family also reportedly owns the large farm in Solebury Township where an active search for the four missing men was launched on Monday. According to their Facebook profiles, DiNardo is friends with Meo. "I can't say if there is in fact that type of information but if there is, I beg of you to please give it to us and let us run it down".
The FBI has been called to aid in the investigation, Mr Weintraub said.
On Monday, police searched the DiNardos' family home in Bensalem in the southern end of Bucks County.
DiNardo was charged Monday with possession of a firearm in Bensalem Township in an unrelated case from the missing men.
An arrest was made at a home on Monday near the property that was being searched.
At least some of the missing men are friends, but it's unclear how well they knew the property owner's son, Cosmo DiNardo, if at all. The district attorney declined to disclose if DiNardo is cooperating with police.
Sturgis and Meo were last seen together Friday night in the Doylestown area. The police also recovered Mr. Sturgis's vehicle, a 2004 Nissan Altima, at an outdoor shopping mall, Mr. Potash said.
Patrick has been missing since Wednesday, while Strugis, Finocchiaro and Meo have been missing since Friday, Weintraub said - adding that there are indications they knew each other, though investigators were still trying to determine if the disappearances were linked.
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He suffers from mitochondrial depletion syndrome, a rare genetic illness which leads to progressive brain and muscle damage. President Trump also weighed in on Twitter, telling Charlie's parents that the U.S.is ready to help any way we can.