Larry Fuller, 57, a black Vietnam war veteran, walked out of court a free man on Tuesday after the legal advocacy group the Innocence Project took up his case.

He was the 10th wrongfully convicted prisoner to be freed in Dallas County based on DNA testing in the past five years.

Fuller was convicted of aggravated rape in 1981 and sentenced to 50 years in prison.

"Any time DNA proves a wrongful conviction, we need to learn what went wrong so it can be prevented in the future. When DNA proves 10 wrongful convictions in one county, the need for reform can't be ignored." said Maddy deLone, the executive director of the Innocence Project.

The Innocence Project said many of these cases involved misidentification involving white victims or eyewitnesses and black suspects.

"That was the case here, Larry Fuller was black and the victim was white," Eric Ferrero, director of communications at the Innocence Project, told Reuters.

Such cases evoke Harper Lee's classic novel "To Kill a Mockingbird", which revolves around the case of a black man accused of raping a white woman in the American South.

According to the Innocence Project, there have been over 180 post-conviction DNA exonerations in the United States since 1989. More than half of these cases have involved African Americans.