A Mexican man was executed in Texas on Wednesday evening for killing a Houston police officer, despite pleas and diplomatic pressure from the Mexican government and the U.S. State Department to halt the punishment.

Edgar Tamayo, 46, received a lethal injection for the January 1994 fatal shooting of 24-year-old police officer Guy Gaddis.

Courts rejected last-day appeals, and Texas officials spurned arguments that Tamayo’s conviction and death sentence were tainted because he did not receive notice that he could request legal help from the Mexican consulate after his arrest for the officer’s slaying.

Attorneys also argued unsuccessfully that Tamayo was mentally impaired, making him ineligible for execution, and that the state’s clemency procedures were unfair.

Earlier Wednesday, Tamayo’s attorneys turned to the Supreme Court after the U.S. Court of Appeals for the 5th Circuit said an appeal this week renewing a contention that Tamayo was mentally impaired and ineligible for execution was filed too late. The Supreme Court also rejected the appeal.

Tamayo’s attorneys argued that the Inter-American Commission on Human Rights, an arm of the Organization of American States, had determined only last week that Tamayo was mentally impaired. Lawyers contended that Tamayo should be granted an exception to court rules that bar such new last-minute appeals.

Gaddis, who had been on the force for two years, was driving Tamayo and another man from a robbery scene when, evidence showed, the officer was shot three times in the head and neck with a pistol Tamayo had concealed in his pants. The car crashed, and Tamayo ran but was captured a few blocks away, still in handcuffs, carrying the robbery victim’s watch and wearing the victim’s necklace.

Records show that the Mexican consulate became involved or aware of the case just as Tamayo’s trial was to begin.

Secretary of State John F. Kerry previously asked Texas Attorney General Greg Abbott to delay Tamayo’s punishment, saying it “could impact the way American citizens are treated in other countries.” The State Department repeated that stance Tuesday.

This was the first execution this year in the nation’s most-
active capital punishment state, where 16 were put to death in 2013.