UPDATED 11/22/11 7:53 a.m.

BRIDGEVIEW, Ill. (CBS) — A Sugar Grove man has been acquitted of the murder of his teenage girlfriend 30 years ago, when the two were attending a program for deaf students together.

As WBBM Newsradio’s Mike Krauser reports, when the judge told Gary Albert he was free to go, he didn’t react at first. Albert had first to see what the judge said from a sign language interpreter.

LISTEN: WBBM Newsradio’s Mike Krauser reports

Jurors deliberated for less than an hour before issuing the verdict.

Albert was 18 on March 22, 1981, and attended a program for the deaf at Hinsdale South High School with his pregnant 15-year-old girlfriend, Dawn Niles, of LaGrange Park.

Niles was found dead in a forest preserve near Horsetail Lake in Palos Township.

She had been stabbed 34 times.

When Niles was reported missing, her mother called Albert, who said they had broken up months before.

The case was reopened in 2006, when a DNA swab indicated that Albert had had sex with Niles before she was murdered.

Prosecutors said Albert killed Niles because he didn’t want to be a father.

Mary Augustyn, Niles’ confidante and fellow deaf student at Hinsdale South, testified that Albert told Niles to tell her mother that she had been raped or had been with another boy.

Albert denied killing Niles, and his attorneys said police rushed to conclusions and ignored other leads and suspects.

The Sun-Times Media Wire contributed to this report.