Gunmen suspected of ties with Mexican drug cartels assassinated the acting head of the country's federal police in an ambush at his home in Mexico City, the Wall Street Journal reported May 9.

Edgar Millan was shot as he entered his home; the killers were waiting for him inside. Millan was named to his post by President Felipe Calderon, who has turned Mexico's police and military to the task of combatting the drug cartels in a battle in which more than 2,500 people have died. Calderon called the killing "cowardly" and said Millan would be remembered as a national hero.

The Sinaloa cartel was suspected in the killing; Millan was involved in a January operation that broke up a cartel plot to assassinate other Mexican officials. Millan was the former head of Mexico's elite anti-kidnapping squad and a former head of the national intelligence agency.

"This guy was a top operations guy. The question is, can you keep replacing guys like this?" said one Mexican security official.