A man who spent 15 years in prison for a crime he says he didn't commit is suing Northwestern University, saying a former professor there tricked him into confessing to a double murder.

“I am angry at the people who did what they did to me,” said Alstory Simon. He was freed from prison nearly five months ago and now hopes to get restitution for the emotional distress he endured spending a decade and a half of his life behind bars.

Simon’s Lisle-based attorneys Terry Ekl and Jim Sotos fought to get Simon released and on Tuesday filed a $40 million federal lawsuit against former Northwestern professor David Protess, among others, claiming Simon was tricked into confessing to a 1982 double murder.

Simon's confession in the high-profile case helped free another death row inmate, Anthony Porter, who served 17 years before evidence surfaced he was innocent, thanks to the investigative work of the Northwestern University professor and his students.

At one point in 1998, Porter was just 48 hours shy of execution when attorneys won a stay by raising concerns about his mental competence at trial.

Now Simon’s legal team says Protess, who overturned wrongful convictions through his university journalism class, used illegal tactics to get Simon’s confession, which freed Anthony Porter from prison.

“Northwestern knew about these activities as early as 1996," Ekl said, "and did not put a stop to anything."

Northwestern said in response to the lawsuit saying it “denies all wrongdoing in this matter and looks forward to being vindicated in a court of law.”

Private investigator Paul Ciolino, who got Simon to confess to the murder on video tape and is among those named in the lawsuit, said in a statement that Simon’s attorneys’ “media spin of the horrific injustice suffered by Mr. Simon is a legalized version of a hold up for a big payday.”

“I don’t have to read this lawsuit to know it is frivolous,” Ciolino added.

Attorney Jim Sotos maintained they have “no problem” with class projects on cases of innocence and understands they are valuable.

“The problem is when you have rogue individuals operating investigative classes that are functioning as investigative agencies outside the boundaries of the law,” Sotos said. “That kind of thing needs to stop.”

Protess could not immediately be reached for a comment.