A man imprisoned since 1981 for sexual assault was freed after a judge recommended overturning his conviction.

Charles Chatman, 47, was released on his recognizance after serving nearly 27 years of a 99-year sentence. He was freed on the basis of new DNA testing that lawyers say proves his innocence and adds to Dallas County's nationally unmatched number of wrongfully convicted inmates.

Chatman became the 15th inmate from Dallas County since 2001 to be freed by DNA testing. That is more than any other county nationwide, said Natalie Roetzel of the Innocence Project of Texas, an organization of volunteers who investigate claims of wrongful conviction.

Texas leads the country in prisoners freed by DNA testing. Including Chatman, the state will have released at least 30 wrongfully convicted inmates since 2001, according to the Innocence Project.