Person of interest named in disappearance of 4 men in Pennsylvania FBI now involved in the disappearance of 4 young men in Pennsylvania counties.

 -- A man arrested Monday is a person of interest in the search for four young men who have vanished, authorities in Bucks County, Pennsylvania, said today.

Cosmo DiNardo, 20, was arrested near a property being searched for the men, and he has been charged with a firearms possession offense from February.

Bucks County District Attorney Matthew Weintraub said this morning that DiNardo is now a person of interest in the search for the missing men but Weintraub stressed that no remains have been recovered.

Investigators are searching a property that belongs to the DiNardo family.

DiNardo is in jail being held on a $1 million bond in connection to the firearms possession allegation, not the men’s disappearance.

Tom Meo, 21, of Plumstead, Mark Sturgis, 22, of Pennsburg, Deam Finocchiaro, 19, of Middletown, and Jimi Tar Patrick, 19, of Newtown Township were all reported missing last week, Weintraub said at a news conference on Monday.

When asked whether foul play was suspected in the case, Weintraub said, "it sure would seem so," but declined to share further information.

“The leads are incredibly hot; they’re very fruitful. We’re making great progress, but there’s so much more work to do,” he said.

"We have information that the four men know each other, but we are not sure if this information is accurate," Weintraub told reporters.

Newtown Township, Plumstead Township, Middletown Township Police and state police are all involved in the joint investigation, Bucks County Assistant District Attorney Gregg Shore told ABC Philadelphia station WPVI-TV.

Sturgis' father said Meo and his son went missing last week after being seen in the Solebury area, according to WPVI. Mark Sturgis’ vehicle was found in the Peddler's Village shopping complex, according to the station. The wooded area being searched is also near Peddler's Village, the station reports.

A missing person's report was filed with the Newtown Township Police Department for Patrick July 6.

Finocchiaro was last seen around 6:30 p.m. Friday getting into a car at Hampton Drive in Middletown Township, according to WPVI.

Weintraub said it is "all hands on deck" to find the four men.

"At this point, I ask for your patience and your prayers for these four young men and let us do our jobs," Weintraub said.