AUBURN — Roy Brown said it wasn’t hard to keep pursuing his freedom, even after a decade and a half behind bars.

“I’m innocent. That’s what kept me going,” Mr. Brown said. “You just can’t give up.”

Fifteen years to the day after he was convicted of a brutal murder, Mr. Brown, 46, was ordered released from state prison on yesterday because DNA tests proved he did not commit the crime.

Cayuga County Court Judge Mark H. Fandrich vacated the murder charges and ordered Brown released on his own recognizance.

Mr. Brown, frail from severe liver disease, remained seated throughout the brief proceeding and did not speak, but more than 40 family members and friends erupted in applause when the decision was announced.

“This was an abortion, an abortion of justice,” Mr. Brown said at a press conference. “They could have saved me all this hell.”

Mr. Brown was convicted January 23, 1992 of beating and strangling Sabina Kulakowski, a social worker who was bitten repeatedly by an attacker who dragged her several hundred feet from the farmhouse where she lived in the Finger Lakes town of Aurelius.

Prosecutors relied mostly on circumstantial evidence and the bite marks on the body to win the conviction. Mr. Brown had been released from county jail a week before the killing after serving eight months for threatening social workers assigned to his child custody case. He claimed he never knew Kulakowski.

Her nude body had bite marks that an expert prosecution witness linked to Mr. Brown, even though they showed indentations from six upper teeth while Mr. Brown has only four.

Mr. Brown was sentenced to 25 years to life in state prison, where he has remained ever since. Mr. Brown always maintained his innocence, and after numerous appeals were rejected, he began trying to solve the crime himself.

Mr. Brown filed a Freedom of Information request four years ago and paid $28.50 for copies of all the documents in his case. He found four affidavits relating to Barry Bench, the brother of Kulakowski’s ex-boyfriend.

Cayuga County District Attorney James B. Vargason ordered Bench’s body exhumed to extract DNA, and he said new tests showed that the samples from Bench matched DNA found on the red T-shirt investigators believe Kulakowski was wearing the night she was killed in 1991.

“This is unlike any case we’ve ever seen,” the co-director of the Innocence Project, a national group that tries to free wrongly convicted inmates, Peter Neufeld, said. “He solved his own case. That’s pretty amazing.”