A soldier guards the main entrance of the local police headquarters during an operation in Monterrey, northern Mexico June 1, 2009. Federal forces ran a joint operation at police headquarters in the municipalities of San Nicolas, Apodaca and Monterrey to detain 70 local police officers who are presumed to be in collusion with organised crime and provide protection as well, according to local media. REUTERS/Tomas Bravo (MEXICO CRIME LAW MILITARY)