SAN ANTONIO, Texas (AP) _ A convicted killer nicknamed ''Spiderman'' will be executed despite the sudden appearance of a mystery witness nearly seven years after the crime, a judge ruled.

District Judge Mike Machado set July 21 for the execution by injection of George ''Spiderman'' Cordova, 27, for the Aug. 4, 1979, beating-stabbing death of Joey Hernandez in Espada Park.

Defense lawyer Don Killingsworth told Machado about the witness at a hearing Wednesday.

''The man stated that Cordova was not at the scene of the crime and named five people who were present,'' Killingsworth said.

''I think his conscience made him'' come forward, said the attorney, who did not name the witness.

Machado did not act on the attorney's report.

''It is a question of fact, and the jury already answered that question,'' the judge said.

Cordova was nicknamed ''Spiderman'' by San Antonio authorities in 1980 when he slithered through a six-inch gap at the Bexar County Jail here, reached the street with a rope made of sheets and escaped while awaiting his murder trial.

He was captured in Florida soon after, but was charged there with the rape of a teacher and sentenced to 30 years in prison.

Cordova was involved in a prison riot in October, 1981 in Florida, authorities said. He was returned to Texas in 1982 for the Hernandez trial, and was convicted and sentenced to death.

During his trial here, bailiffs discovered that he had obtained a key to his handcuffs in what authorities believed was another escape attempt.

Cordova appealed his murder conviction and death sentence, but the Texas Court of Criminal Appeals upheld the verdict and his execution was set for Jan. 8.

Five days before Cordova was to be executed, U.S. Supreme Court Justice Byron White issued a stay of execution. Last month, the full Supreme Court refused to hear arguments that Cordova was wrongly sentenced to death.