Wave of drug violence targets Mexican police

In recent days, some of Mexico's top police officials -- from the federal, state and local level -- have been assassinated in what crime experts call a clear escalation of bloodshed a year and a half into President Felipe Calderon's war against drug traffickers.

Police investigators believe that powerful organized crime rings have penetrated federal security agencies and are obtaining top secret information from inside informants about the location of police commanders. Once cartel hit men have such intelligence, they strike.

Authorities say that was the case with the brazen May 8 assassination of federal officer Edgar Millan, who served as acting director of the Federal Preventive Police and oversaw the arrests of top members of the Sinaloa cartel. The gunmen knew exactly when and where Millan would be the night they surprised him inside his own home and filled his body with 9 bullets.

Now there's growing concern that these most recent violent crimes targeting police authorities will strike fear into security officers across Mexico and make it difficult for the government to fill the posts held by the recently slain commanders.