Transit officers are reflected on the hearse after a memorial ceremony for their slain colleagues at the police headquarters in Monterrey January 31, 2011. Two officers were gunned down late Saturday by hitmen after stopping a vehicle for an inspection, according to local media. At least 100 people, including 18 policemen, have been killed in drug violence in the city and its environs since New Year's Day. REUTERS/Tomas Bravo (MEXICO - Tags: CIVIL UNREST CRIME LAW)