SHERMAN, Texas—A death row inmate condemned for a 1983 quadruple slaying has won his request for DNA testing on old evidence he believes could point to other suspects.

A state district judge Friday said that Lester Leroy Bower Jr. “would not have been convicted” if genetic testing linked others to a North Texas airplane hangar where four men were found shot execution-style. DNA testing wasn’t available in 1984 when Bower stood trial.

Prosecutors had called the request a ploy aimed at delaying Bower’s execution, which had been set for July 22. Attorneys for Bower, a chemical salesman with no prior criminal record, believe the crime may have been committed by four other men in a dope deal gone bad.

“The interests of justice are too great to ignore the prospect that the evidence may contain the DNA of one of these four named individuals,” state District Judge Jim Fallon said in his ruling, reported by the Fort Worth Star-Telegram.

Bower’s attorneys sought testing on hair, saliva and cigarette butts found in the hangar at the B&B Ranch north of Dallas.

Bower was convicted after prosecutors built a circumstantial case surrounding Bower’s purchase of an ultralight airplane from one of the victims. No fingerprints put Bower at the scene, no witnesses saw him there and a murder weapon never was recovered. Prosecutors say he simply snapped.

Among the issues yet to be resolved is how genetic samples can be collected from the four men Bower’s attorneys say could be suspects.