The heir to a real estate fortune confessed to the killings of four men after a police investigation found human remains on his family's estate in Bucks County.

Cosmo DiNardo, 20, was arrested Wednesday in connection with the disappearance of Mark Sturgis, 22, Thomas Meo, 21, Dean Finocchario, 19, and Jimi Tar Patrick, 21. After police dogs discovered remains of three victims buried in a deep "common grave" at the 90-acre family farm in Solesbury, DiNardo confessed to the killings and told police where to find the fourth victim in order to avoid the death penalty, NBC 10 reports.

DiNardo's grandfather, also named Cosmo, began investing in commercial and residential real estate in the 1970s, and has amassed property holdings in Bucks, Montgomery and Philadelphia counties. By the early 1990s, the elder Cosmo DiNardo had passed the business along to his son Antonio. Among the family's holdings is a facility leased to a behavioral health nonprofit in Northeast Philadelphia and an apartment complex in Jenkintown.

DiNardo allegedly sold marijuana and guns after dropping out of Arcadia University in 2015 and being banned from campus. He shot and killed each of his victims separately after marijuana deals, according to the Associated Press, and he told prosecutors he worked with an accomplice. Another person has been taken into custody in connection with the case, the Philadelphia Inquirer reports.

In February, DiNardo was arrested for illegal possession of a shotgun; he was reportedly banned from carrying firearms because of his history of mental health issues that included involuntary commitment to a psychiatric facility. Charges were dropped in May, but DiNardo was brought back in on the same charges Monday. After being released on bond Tuesday evening, DiNardo was arrested once again Wednesday for attempting to sell a car belonging to Meo. Since then, he's been held on $5M bail.