CHICAGO (CBS) — The Chicago police union has asked the Cook County State’s Attorney’s office to examine a milestone double murder case, to see if the right man is behind bars.

WBBM Newsradio’s Steve Miller reports Anthony Porter had been on Death Row for a 1982 double murder, and then freed in 1999, when another man confessed to the crime.

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Porter’s case was a key factor in former Gov. George Ryan’s decision to enact a moratorium on capital punishment in 2000, and clear out Death Row three years later. That decision ultimately led to Illinois abolishing the death penalty in 2011.

The other man who confessed to the murders that put Porter on Death Row was Alstory Simon, who has since said his own confession – to students and a private investigator with Northwestern University’s Innocence Project – was coerced. Witnesses also have since recanted.

“If this was a wrongful conviction where a police officer was accused of coercing a confession from somebody, it would be opened in a heartbeat,” said Chicago Fraternal Order of Police spokesman Pat Camden.

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Camden said the FOP wants Cook County State’s Attorney Anita Alvarez to take a new look into the case.

“The bottom line becomes – justice needs to be served,” Camden said.

The FOP sent a letter to Alvarez, saying “many police officers… believe (Alstory) Simon is the wrong offender.”

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“His case needs to be reexamined,” Camden said. “They’ve done it over and over again on cases of alleged brutality and torture. They need to be able to do it in this case as well.”