Cadaver dogs led police to the makeshift grave on the 90-acre property along Route 202 in Solebury Township where several law enforcement agencies, including the Federal Bureau of Investigation, have been searching for any signs of the missing men, according to Weintraub.
The body has been identified as 19-year-old Dean Finocchiaro.
Earlier Wednesday, Weintraub said police would "continue digging and searching that property until we're satisfied that they are not there". He wouldn't say what evidence has been recovered, but did note it didn't include human remains. "We are going to bring each and every one of these lost boys home to their families - one way or another - and we will not rest until we do that". The other three are identified as Mark Sturgis, 22, Thomas Meo, 21, and Jimi Tar Patrick, 19. One of the missing, Patrick, attended a Catholic high school for boys with the suspect.
The back-to-back arrests bought investigators time as they scoured the farm and other spots across the county for clues to the men's disappearance, Weintraub said.More news: Mithali Raj becomes highest run scorer in ODI
Authorities say the search is intensifying on a sprawling farm for four missing men in Pennsylvania.
The police have a person of interest in the case; Cosmo DiNardo, 20. DiNardo's family owns the 90-acre property on the 6000 block of Lower York Road in Solebury where Finocchiaro's remains were found. Authorities said DiNardo attempted to sell the vehicle on July 9, for $500. Both young men didn't go to work on Saturday, police said. DiNardo was arrested on Monday on unrelated firearms charges and was held in jail with a bond of $1M. His bail was set at $5 million cash after Weintraub argued he was a flight risk.
Finocchiaro was last seen Friday around 6 PM getting into a vehicle and has not been seen or heard from since. "We just don't know how many homicides", Weintraub said.
Close friends Sturgis and Meo were last seen near the Doylestown area in Bucks County, CNN affiliate KYW-TV reported. Then, on Wednesday, authorities arrested DiNardo again, accusing him of stealing and trying to sell a 1996 Nissan Maxima that belonged Meo, according to the Bucks County District Attorney's Office.More news: Facebook, Google, Netflix take part in United States net neutrality 'day of action'
Weintraub said a number of sites are now under investigation.
In the February gun charge he still faces, DiNardo is accused of illegally being in possession of a shotgun and ammunition because of a previous involuntary commitment to a mental health institution. Little has been said about how all the young men are connected or what might have led to the disappearance of the four.
Later he said: "Take the biggest (investigation) you've ever seen and multiply it by a million". Sturgis and Meo worked together at Sturgis's father's construction business, and Finocchiaro was said to have been a mutual friend of the two, according to the Philadelphia Inquirer.More news: Smith' Facebook 'Hacker' Message Is Latest Social Media Hoax