For nearly 15 years, a man on death row in Texas has sought DNA testing to try and prove he did not kill an 85-year-old woman.

Ruben Gutierrez is challenging the constitutionality of a state law that restricts death row inmates from seeking tests that he says will prove he’s not a murderer.

Ruben Gutierrez's lawyers say new evidence tests would help prove he was not responsible for the fatal stabbing of an 85-year-old woman in South Texas.