HOUSTON -

 A judge has set the execution date of a man that is accused of killing a Houston police officer.

Edgar Tamayo was convicted of killing HPD Officer Guy Gaddis back in 1994.

Authorities said while in the back of squad car, Tamayo took out a hidden gun and shot Officer Gaddis in the back.

U.S. Secretary of State John Kerry had sent a letter to the judge asking him not to set an execution date because Tamayo is a Mexican citizen, but the judge on Tuesday set Tamayo’s execution for January 22, 2014.