A Texas inmate is scheduled to be executed for killing a suburban Dallas police officer after he and six others broke out of prison.

Attorneys for 52-year-old Donald Newbury are asking the U.S. Supreme Court to halt his Wednesday evening lethal injection.

Newbury is to die for the fatal shooting of 29-year-old Officer Aubrey Hawkins, who interrupted the "Texas 7" as they robbed an Irving sporting goods store on Christmas Eve 2000.

Newbury would be the third gang member executed for the killing. Three others remain on death row. One shot and killed himself in January 2001 as authorities closed in after tracking the gang to Colorado.

The captures and suicide came about six weeks after the largest prison break in Texas.