A judge has ruled that the Bexar County district attorney should be allowed to investigate whether Ruben Cantu was wrongly executed in 1993.
State District Judge Mary Roman says she found no due process violation that would prompt District Attorney Susan Reed's disqualification.
Keith Hampton, the attorney for convicted Cantu co-defendant David Garza, had argued that Reed should be disqualified in part because she was involved in the case earlier as a judge. At the time, she did not grant Cantu a hearing on a legal filing, and she set his execution date.
Cantu maintained his innocence for the fatal shooting of one man and critical wounding of another in 1984. He was convicted of capital murder in 1985.
Reed reopened the case last year after a newspaper published claims of wrongful execution.
The Texas Court of Criminal Appeals in August refused to rule on Reed's involvement in the case.