A schizophrenic man has confessed to killing four friends and burning their bodies before burying them on his family's farm.

Cosmo DiNardo, 20, confessed to the four murders after detectives found the body of one of the missing men, alongside human remains in the same grave on the property in Pennsylvania. 

He told authorities where the bodies were located after revealing he felt cheated and threatened during a cannabis deal gone wrong. 

The 20-year-old is prepared to plead guilty to four counts of first-degree murder. 

The revelation comes after an investigators charged DiNardo with trying to illegally sell the car belonging to one of the missing young men.

A co-conspirator has now been arrested, AP reports. 

The person spoke to AP on the condition of anonymity because he wasn't authorized to publicly discuss details of the case.   

FBI dectectives combed the 70-acre farm north of Philadelphia and spent several days digging up the grave and sifting through for evidence. 

Bucks County District Attorney Matt Weintraub said: “This is a homicide; make no mistake about it. We just don’t know how many homicides.”

The body of Dean Finocchiaro, 19 was found in the 12.5 ft common grave.

Also missing are Mark Sturgis, 22, Tom Meo, 21, and Jimi Tar Patrick, 19.

Patrick, who attended a Catholic high school for boys with DiNardo, was last seen Wednesday, while the other three vanished Friday.

Earlier charges stem from accusations DiNardo was found with a shotgun and ammunition in February despite a prior mental health commitment. An affidavit in that case said he is “known to be suffering from mental illness.”

DiNardo was charged after authorities, using license tag tracking devices, found Meo's 1996 Nissan Maxima on the same farm where the body was discovered.

His bail was set at $5 million cash Wednesday in connection with the stolen car.

On Tuesday, DiNardo was released on $1 million bail on an unrelated gun charge.

Eric Beitz, 20, of Bensalem, Pa., said Wednesday that he and his friends recently spent time with DiNardo, who seemed to have “ulterior motives.”

“I can tell you on multiple different occasions, on multiple different accounts, from multiple different people, including myself — Cosmo has spoken about weird things like killing people and having people killed,” Beitz told The Philadelphia Inquirer.

“Everybody you talk to about this guy, you hear he’s mentally unstable.”

According to Beitz, DiNardo also sold marijuana and guns, and aggressively sought new customers. 

DiNardo’s parents, Antonio and Sandra DiNardo, own the farm in upper Bucks County, a bucolic area with rolling hillsides, new housing developments and historic sites. 

An attorney representing the couple issued a statement earlier Wednesday saying they sympathize with the families of the missing men and are cooperating “in every way possible with the investigation.”