For more than two decades behind bars, Willie Earl Green worked hard on his education, married his pen pal and never stopped trying to prove he was innocent in the execution-style murder of a single mother. The sole prosecution witness came forward four years ago, saying he was not sure he had identified the right man. Last week, a judge tossed out Green's conviction. Even though he spent nearly half of his life in prison, the 56-year-old, soft-spoken man is at peace with himself. "I was wrongly accused, I'm out now, I'm not bitter, I'm happy. This is the best thing that ever happened to me right here," Green said as he left the courthouse. Green, a former chauffeur from Canton, Mississippi, said he was proud of his achievements in prison, including earning an associates degree and teaching math to fellow inmates at San Quentin. "I'm a better man today," Green said upon his release on Thursday. "I graduated from college. I'm proud of that accomplishment. I teach school. I teach men that a whole lot of people gave up on." He said he looks forward to spending time with his wife, Mary, and taking care of her as she battles breast cancer. They married in 1991. "Today, the honeymoon begins," Mary Green declared. When asked whether the criminal justice system failed him, Green replied: "The same system that put me in jail is the same system that got me out." Willie Finley, a convicted murderer and drug dealer, said he had been high on crack at the time of the killing and did not get a good look at the assailant because his eyes were impaired from a pistol whip. He also said a detective coached him to identify Green in a photo lineup. Last week, Superior Court Judge Stephen A. Marcus found that Green did not receive a fair trial because jurors never heard Finley's full story, which probably would have swayed them when they were evaluating the witness' credibility. The judge threw out Green's conviction in the 1983 murder of Denise "Dee Dee" Walker, 25, in a South Los Angeles crack house. The Los Angeles County district attorney's office said Wednesday it would not oppose his release. Green had been sentenced to 33 years to life in prison and served nearly 25 years behind bars.