The chief of investigations for the Mexican border state of Tamaulipas is dead after a late-night gunbattle that also killed four gunmen.
The state government says police investigator Salvador de Haro Munoz was killed late Monday in the state capital, Ciudad Victoria.
Three marines and a military police officer were wounded in the confrontation.
De Haro Munoz and other officers had gone to investigate a home apparently used by a criminal gang.
The gang began shooting and the officers returned fire.
After the gunbattle, five suspects were detained, including two women.
Tamaulipas has been the scene of bloody turf battles between the Gulf drug cartel and the Zetas drug gang.
Once one of Mexico's most violent states, Tamaulipas had calmed somewhat before violence re-ignited in recent weeks.