Forty-eight year old Christopher Abernathy is a free man on Wednesday, after spending nearly 30 years in prison for the 1984 slaying and sexual assault of a 15-year-old Chicago girl. The judge threw out charges against Abernathy after DNA testing done last August excluded him from every piece of evidence in which DNA was obtained. Abernathy had been sentenced to life in prison in 1987.

Kristina Hickey was a high school student who disappeared after a choir concert at her Park Forest school. her body was found two days later. Abernathy was arrested more than a year after the murder. He signed a confession after more than 40 hours of interrogation, and later recanted, saying he was coerced into signing the document. Abernathy had dropped out of school at age 15 and had documented learning disabilities, according to his attorneys.

Abernathy was 18 when he was arrested. He knew the girl and was questioned early in the investigation, but was released without charges. A year later he was arrested and charged with murder. The Illinois Innocence Project worked on Abernathy’s case for over a year, and asked the state’s attorney’s Conviction Integrity Unit to perform DNA testing. One of his attorneys, Lauren Kaeseberg, said that he was told by the only way he would be able to see his mother again was by signing a confession.

Prosecutors re-interviewed witnesses and studied old police records and court transcripts. They found that Abernathy “may have suffered from a diminished mental capacity” at the time he made the confession.

After 29 years, Abernathy walked out of the prison and straight into his mother’s arms, who said she always knew in her heart that her son was innocent. According to Kaeseberg, Abernathy is looking forward to spending time with family, living a normal life and enjoying some quiet, open space. He also wants to eat a “real” cheeseburger.

Abernathy did not find out about the prosecutor’s decision until Wednesday morning. The state attorney’s office says it will be opening a cold-case investigation into the murder of Kristina Hickey.