Pennsylvania State Police conducted a search at a home in Solebury Township Sunday evening when they located a vehicle belonging to one of the teens in a garage, FOX 29 reported. "As of this moment, [DiNardo] remains a person of interest, but others arise and we can name them, we will".
The gun charge is unrelated to the missing persons case, the Associated Press reports.
The missing men's photo have begun to appear on digital billboards along highways in the area. According to Sturgis' father, Mark Potash, Sturgis and Meo are longtime friends who work in construction for him.
The fourth person to vanish was Dean Finocchiaro, 18, who was last seen in Middletown Township around 6:30 p.m. on Friday.
Jimi Tar Patrick, 19, of Newtown Township, was the first to go missing last Wednesday.
He admitted it may take days before more information comes to light, though he said the leads are "incredibly hot and fruitful".
The police and Mr. Weintraub's office cast a wide net, searching throughout the county and requesting the public's help on social media.
As a condition of his bail, DiNardo provided authorities his parent's home on the 900 block of Wayland Circle in Bensalem as his current address.
Weintraub would not say if investigators have spoken to the DiNardo family or if the investigation has led them to Cosmo DiNardo.
Their son, Cosmo Dinardo, 20, was arrested Monday on a charge of possession of a firearm, an offense dating back to February.
The family of DiNardo, 20, of Bensalem, owns both Solebury properties that have been searched thus far.
Meo and Sturgis were known friends. He also said that based on information that he "can't share", foul play was likely involved in the disappearance of the young men.
Since that press conference, more news has come out, as an arrest has been made while the search for the four young men continues. A district judge dismissed the charge in May, but the district attorney authorized for it to be refiled on Monday.
Bucks County District Attorney Matthew Weintraub said the Federal Bureau of Investigation has joined the search for evidence due to their expertise in recovery operations at the primary search site.
The district attorney declined to say if DiNardo's parents, Sandra and Antonio, have been subpoenaed, or if their cellphones were seized.
He was last seen around Routes 202 and 263 near Doylestown on Friday, she wrote.
Federal authorities said Tuesday they are no longer investigating a pipe bomb explosion that damaged a northeast Oklahoma Air Force recruiting station as a possible act of domestic terrorism, adding that the blast could be the work of a disgruntled employee or a prank. It's unclear what, if any, connection the disappearances might have, but investigators did confirm that the four men know each other.
The families of the missing men have been waiting for answers.
Weintraub said Tuesday that hundreds of law enforcement officials - including members of the state police, U.S. Marshals and the Federal Bureau of Investigation - are involved in the search for the four missing men.