On Monday, Cosar got his opportunity.
Former Oklahoma Gov. Brad Henry, who commuted Cosar's life sentence and signed his parole, surprised the ex-convict by dropping by the classroom where Cosar now teaches life skills to other former inmates.
"This is a shock. You're going to make me start crying," Cosar told Henry as the ex-governor strolled into Cosar's small teaching space at The Education and Employment Ministry. "I really just want to thank you."
Cosar was convicted and sentenced to life in prison in 1986 for the shooting death of an Ada man after a night of drinking when Cosar was 19 years old.
"There are many clear indicators of success outside of the prison walls. People can overcome their challenges and be successful," Henry said. "I wasn't the least bit concerned that he wasn't going to succeed and become the person who he is.
"He made a mistake way back when, and he paid the price and learned from that mistake, and now he's helping other people."
In an unusual move, Pontotoc County District Attorney Chris Ross, who was a young prosecutor when he sent Cosar to prison, said his office did not object to Cosar's parole the second time he was eligible to be released.
"He may be the only person I've ever put in prison for life for murder that I haven't protested," Ross said in a telephone interview with The Associated Press. "It was a deal where I looked at what he'd done, how young he was. I looked at his prison record and his conduct and what he'd done while he was in prison.
"I'm glad to hear he's doing well. I hope he continues."
Now married and living in Bethany, Cosar, 47, teaches courses on workforce and relationship skills, anger management and how to transition to life outside of prison for TEEM. About 70 percent of the nonprofit group's clients are ex-convicts, and Cosar began working there after his release.
"It's a unique skill set to be able to identify and relate and also demand their best at the same time," TEEM's executive director, former Oklahoma House Speaker Kris Steele said of what Cosar brings to the job.
Inside Cosar's classroom, signs hang on the wall that read "Forgiveness," "Tolerance" and "Virtue." A photograph of a gruff looking former Oklahoma prison warden Ray Little, a man Cosar described as a mentor, leans against a green chalkboard.
When Steele started at the agency about six months ago, Cosar told him he wanted to meet Henry and thank him for giving him another chance. Steele, a Republican from Henry's hometown of Shawnee, said he mentioned a possible meeting to the former governor, but it didn't become a reality until after Henry's daughter, Laynie, began working at the agency.
"I reached out shortly after I started here, but I think Laynie gets most of the credit for it," Steele said. "She closed the deal."
The Education and Employment Ministry: www.teem.org
Sean Murphy can be reached at www.twitter.com/apseanmurphy