Lucio Cuevas Sanchez was detained on suspicion of illegal public service and of a crime committed within a prison, the El Paso Times reported Wednesday.
Seventeen inmates, including two U.S. citizens, died in a prison riot July 25. The armed battle between gangs at the Cereso prison was first reported as a breakout. Media reports at the time said some of the prisoners may have been wearing guard uniforms. Mexican federal police entered the facility to restore control, while Juarez police and the army closed off surrounding streets.
Chihuahua state and Mexican federal officials said four Cereso guards were arrested -- two for allegedly committing crimes in prison, one for alleged illegal public service and one for alleged favoritism.
Two Cereso inmates also were being held as suspects in the deaths, officials said.