BUCKS COUNTY, Pa. (CBS/AP) –A man has confessed to killing four men in Pennsylvania separately after selling them marijuana and then burning their bodies at his family’s farm, a person with firsthand knowledge of his confession told the Associated Press on Thursday.

Attorney Paul Lang says his client Cosmo DiNardo confessed to killing Jimi Patrick, 19, Tom Meo, 21, Dean Finocchiaro, 19, and Mark Sturgis, 22. Lang added that DiNardo told authorities where their bodies are located.

In exchange, DiNardo will not face the death penalty.

“Mr. DiNardo, this evening, confessed to the district attorney. He confessed to his participation or commission of the murders of the four young men. In exchange for that confession, Mr. DiNardo was promised by the district attorney that he will spare his life by not evoking the death penalty,” said Lang.

The person with firsthand knowledge of DiNardo’s confession said the men were shot in the head or the back after DiNardo felt cheated or threatened during three drug transactions. DiNardo sold quarter-pound (113-gram) quantities of marijuana for several thousand dollars and sold handguns to area residents, the person said.

“Every death was related to a purported drug transaction, and at the end of each one there’s a killing,” the person said.

DiNardo said one victim was killed July 5 and the other three were killed July 7, the person said. The remains of the last three killed were reported discovered Wednesday by investigators, and DiNardo agreed to tell investigators the separate location of the first victim’s body, the person said.

The bodies were allegedly burned on the family’s farm.

The person spoke to The Associated Press on the condition of anonymity because he wasn’t authorized to publicly discuss details of the case. The person said a co-conspirator was involved in the shooting deaths of three of the men, who had been reported missing.

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After walking out of court on Thursday, DiNardo’s only words were, “I’m sorry.”

BREAKING: DiNardo just walked out. Told me he's sorry. Admitted to killing 4 men. @CBSPhilly pic.twitter.com/v9ay3lV7rp — David Spunt (@DavidSpuntCBS3) July 13, 2017

Early Thursday morning, Bucks County District Attorney Matt Weintraub announced during a midnight press conference that Finocchiaro’s body was discovered in a 12-foot-deep common grave that also contained other human remains on the DiNardo family property in Solebury Township.

Investigators continued to focus on a spot identified by cadaver dogs.

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Weintraub says investigators have not yet identified the other remains found in the deep grave.

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“They’re combing through vast fields and buildings. They’re down 12-foot deep in a hole that’s getting deeper by the minute,” said Weintraub. “They’re tenderly, painstakingly, reverentially recovering the remains of people they do not even know, that they never even met.”

Finocchiaro’s friends have been collecting messages and memories written on pieces of construction paper, which they say they plan to give to his family.

“The only reason I’m not crying right now is because if I cry, Dean would be mad at me saying, ‘Don’t cry for me bro,” said Daniel Balbuena, who says he worked with Finocchiaro.

“It’s a crazy thing man, I can’t even believe it. Last week we were working together, now he’s gone,” Balbuena said.

Patrick’s family released a statement Thursday morning after human remains were found on the property.

“He recently completed his freshman year at Loyola University, MD. Majoring in business, Jimi attends Loyola on a full scholarship and was awarded academic recognition on the Dean’s list,” the family said in a statement.

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Mark Sturgis’ stepmother posted on Facebook saying she hopes, “We will get justice for our boys and our families.”

Sturgis and Meo were last seen together on the night of July 7 in the Doylestown area. The pair are longtime friends who work in construction for Sturgis’ father, Mark Potash. Dean Finocchiaro, is a mutual friend of theirs, Potash told The Associated Press. Potash said he did not know where his son was heading or what he was doing before he disappeared Friday.

Jimi Patrick and DiNardo had attended the same Catholic high school for boys.

It’s unclear if Patrick was friends with the other missing men.

Cosmo DiNardo is being held on $5 million cash bail for allegedly stealing Meo’s car and trying to sell it for $500.

Source: Cosmo DiNardo Barred From University In 2016 After Complaints Were Filed

CBS3 confirmed DiNardo’s parents — Antonio and Sandra DiNardo — were subpoenaed to appear before a grand jury on Thursday.

They declined to comment after leaving a government building where he spent several hours with the district attorney and other investigators.

Police sources tell CBS3 that DiNardo has exhibited violent tendencies and has not been cooperating with the investigation.

Anyone with any information is asked to call the FBI tip line number: 1-800-CALL-FBI and then hit Option 7.

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