A Mexican federal police official has been arrested by U.S. officials as a material witness in the torture-murder of American drug agent Enrique Camarena. Mario Martinez Herrera, a commander in the Mexican equivalent of the FBI, was arrested after dining at a Chula Vista restaurant, his attorney Michael Patrick Murray said. Murray said Martinez is expected to be called Friday to testify before a federal grand jury in San Diego. Camarena, a federal Drug Enforcement Administration agent on assignment in Mexico, was kidnaped in front of the U.S. Consulate in Guadalajara on Feb. 7, 1985, and driven to the house of a notorious Mexican drug trafficker, where he was killed. His body was found in a field in Guadalajara a month later.