Cosmo DiNardo, the main suspect in a case of four missing men in Pennsylvania, admitted to their murders on Thursday. The four men went missing a week ago and DiNardo became the main suspect after attempting to sell one of the victim’s cars.

“I’m sorry,” DiNardo said while leaving a Pennsylvania court Thursday.

DiNardo, 20, confessed to the four murders to police investigators, according to his attorney Paul Lang. DiNardo also told investigators where the four bodies were buried.

DiNardo, who allegedly killed the victims after selling them marijuana, according to the BBC, felt cheated during the illegal transaction. He killed them separately, burned their bodies, and buried the remains on his family’s 90-acre farm in Solebury Township, Bucks County, Pennsylvania, a suburb of Philadelphia.

Three of the victims, Mark Sturgis, 22, Tom Meo, 21, and Dean Finocchiaro, 19, went missing on July 7 while the fourth victim Jimi Tar Patrick, 19, went missing two days earlier.

Finocchiaro’s remains are the only ones to be identified thus far, but the remains of the others have been found. The hole in which the remains were buried, according to DiNardo’s confession, is 12 and a half feet deep and was discovered by police dogs.

“We had cadaver dogs, and I don’t understand the science behind it, but those dogs could smell these poor boys twelve-and-a-half feet below the ground,” District Attorney Matthew Weintraub said during a press conference.

For his participation, prosecutors have agreed not to seek the death penalty against DiNardo, according to Lang.

DiNardo is said to be dangerous and have schizophrenia, according to the BBC.

Meo and Sturgis were both employed by Sturgis’ father’s construction firm. Finocchiaro was a mutual friend of theirs. DiNardo is suspected to have known Patrick through school – they both attended the same Catholic High School for boys.

On Thursday night Sean Kratz, 20, was taken into custody as a person-of-interest in the case, according to a local media report.