Cook County judge agrees to vacate life sentence against man in Park Forest teen's 1984 death

This undated photo provided by the Illinois Department of Corrections shows Christopher Abernathy. Cook County State's Attorney Anita Alvarez's office plans a news conference in Chicago, Wednesday, Feb. 11, 2015, to announce they will dismiss charges against Abernathy, who has been serving a sentence of life in prison for the 1984 murder and sexual assault of a 15-year-old girl. Alvarez's office says she will vacate the sentence after new evidence developed. (AP Photo/Illinois Department of Corrections) (The Associated Press)

Christopher Abernathy is released from the Stateville Correctional Center, Wednesday, Feb. 11, 2015, in Crest Hill, Ill. Abernathy was released after charges were dismissed against him for the 1984 sexual assault and murder of a 15-year-old suburban Chicago girl. The 48-year-old has been in prison since 1987, after being sentenced to life for the death of a Park Forest High School student. (AP Photo/Chicago Tribune, Terrence Antonio James) MANDATORY CREDIT; CHICAGO SUN-TIMES OUT; DAILY HERALD OUT; NORTHWEST HERALD OUT; JOLIET HERALD OUT; THE TIMES OF NORTHWEST INDIANA OUT; NEW YORK TIMES OUT; TV OUT; MAGS OUT; NO SALES; DAILY CHRONICLE OUT (The Associated Press)

Sergio Serritella, left, a private investigator, guides Christopher Abernathy into a waiting car after he was released from the Stateville Correctional Center in Crest Hill, Ill, on Wednesday, Feb. 11, 2015. Abernathy, who spent nearly 30 years in prison for the 1984 sexual assault and slaying of a 15-year-old suburban Chicago girl has left prison a free man after a judge threw out charges against him. (AP Photo/Chicago Tribune, Terrence Antonio James) MANDATORY CREDIT; CHICAGO SUN-TIMES OUT; DAILY HERALD OUT; NORTHWEST HERALD OUT; JOLIET HERALD OUT; THE TIMES OF NORTHWEST INDIANA OUT; NEW YORK TIMES OUT; TV OUT; MAGS OUT; NO SALES; DAILY CHRONICLE OUT (The Associated Press)

Charges have been dismissed against a man who spent nearly 30 years in prison for the 1984 sexual assault and murder of a 15-year-old suburban Chicago girl.

A Cook County judge on Wednesday agreed to a prosecutor's request to vacate the life sentence given to Christopher Abernathy.

The 48-year-old has been in prison since 1987, after being sentenced to life for the death of Park Forest High School student.

The Illinois Department of Corrections says it received a court order to release Abernathy, who's been held in Stateville Correctional Center.

The case is part of the prosecutor's Conviction Integrity Unit that was created in 2012 to reinvestigate wrongful or questionable convictions.

DNA testing in August 2014 excluded Abernathy. His attorneys also said the person who originally accused Abernathy has recanted.