HUNTSVILLE, Texas — A three-time convicted robber who helped engineer the biggest prison break in Texas history has been executed for killing a suburban Dallas police officer while the gang was on the run 14 years ago.

Donald Newbury became the third member of the group known as the “Texas 7” executed when he was given a lethal injection Wednesday evening.

Newbury was sentenced to die for the fatal shooting of 29-year-old Aubrey Hawkins, an Irving officer who interrupted the fugitives’ robbery of a sporting goods store on Christmas Eve in 2000.

The slaying occurred 11 days after the convicts escaped. The gang was captured a month later in Colorado.

The 52-year-old Newbury’s execution was carried out after the US Supreme Court rejected a last-day appeal from his attorneys.