By Jon Herskovitz
AUSTIN, Texas (Reuters) - A man who was in a group of seven inmates behind one of the biggest prison escapes in Texas history is set to be executed on Wednesday for taking part in the murder of a suburban Dallas police officer on Christmas Eve 2000.
Donald Newbury, 52, is set to be executed by lethal injection at the state's death chamber in Huntsville at 6 p.m. CST. If the execution goes ahead, it will be the 521st in Texas, the most of any state since the U.S. Supreme Court reinstated the death penalty in 1976.
Newbury was part of what was known as the "Texas Seven," a group that overpowered 14 prison employees, tied them up and then broke out of the Connally Unit, about 60 miles southeast of San Antonio.
Group members then went on a crime spree for the next several weeks that included the armed robbery of a sporting goods store in the Dallas suburb of Irving.
Irving Police Officer Aubrey Hawkins, who had just finished a Christmas Eve dinner with his family, pulled up to the store in response to a call of suspicious activity. He was shot in his vehicle, pulled out of the car and shot again repeatedly, dying on the pavement, court papers said.
The group then fled to Colorado, where its members ere eventually apprehended. One member of the group committed suicide rather than be captured.
The remaining six members were sentenced to death for Aubrey's murder. Two have already been executed.
Lawyers for Newbury have been seeking a stay, saying his trial counsel did not do a proper job defending him.
"Newbury confessed to his role in the escape and robbery and blamed poor police training for Officer Hawkins's murder," the 5th U.S. Circuit Court of Appeals wrote in 2014 when considering a request for a stay.
Newbury had been serving a 99-year sentence for armed robbery at the time of his escape, the Texas Attorney General's Office said.
Since being on death row, Newberry has been involved in more than 50 disciplinary incidents, including 13 cases of assaulting staff members, five cases for weapons possession and one case of helping incite a riot, the Texas Department of Criminal Justice said.
(Reporting by Jon Herskovitz; Editing by Peter Cooney)