At 66, a former death row inmate — whose exoneration led Illinois to abolish the death penalty in Illinois — has died.

His former attorney Jim Montgomery said that Anthony Porter passed away this week.

“Tony lived a very difficult lifestyle. Montgomery stated that he was a man who grew up on the streets and didn’t make any changes to his life after he left the penitentiary.

According to the Cook County Medical Examiner’s Office Porter died of an “anoxic head injury, probable opioid poisoning.” Porter’s death was ruled accidental.

Porter was sentenced for the 1982 murders of Marilyn Green and Jerry Hillard, a couple from Chicago’s South Side.

He was just two days away from being executed in 1998 when a judge granted a stay to his lawyers. They argued that his low intelligence meant he wasn’t able to understand why he was being executed.

After almost 17 years of being on death row, Porter was exonerated. Alstory Simon, another man, confessed in a Northwestern University investigation to the double murder.

Simon was convicted in 1999 and sentenced to 37 years imprisonment.

The Cook County State’s Attorney’s Office reexamined Simon’s conviction after he renounced his confession. He claimed that he was tricked by a private investigator working with David Protess (a Northwestern journalism professor).

Simon claimed that the investigator told him that he would only serve a brief sentence and would get a portion of the proceeds from the book and movie deals. Simon is strongly denied being framed by the investigator and is suing him for defamation. His attorney was contacted to provide a comment.

Simon was released from prison in October 2014. The crimes of Hillard and Green are still unsolved.

Anita Alvarez, the then State’s Attorney, stated that the investigation into Simon’s case had been “so deeply corrupted and corroded that it is impossible to maintain the legitimacy” of her conviction at a press conference in 2014.

Alvarez said that Simon’s case was tainted because of the questionable methods used by Protess who left Northwestern in 2011. The Northwestern investigation was examined in A Murder in the Park (2014) documentary.

Porter was released and filed a federal civil rights suit against Chicago. According to the Chicago Tribune, Porter filed a federal civil rights lawsuit against the city of Chicago.

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Porter’s 1999 exoneration reignited debate over Illinois’ death penalty and helped to persuade the former governor. George Ryan stopped all executions in Illinois. Ryan commuted all death sentences to life imprisonment in 2003, just before he resigned from office.