Drug lords go after Mexican police officers

Drug cartels are sending a brutal message to police and soldiers in cities across Mexico: Join us or die.

The threat appears in recruiting banners hung across roadsides and in publicly posted death lists. Cops get warnings over their two-way radios. At least four high-ranking police officials were gunned down this month, including Mexico's acting federal police chief.

Mexico has battled for years to clean up its security forces and win them the public's respect. But Mexicans generally assume police and even soldiers are corrupt until proven otherwise, and the honest ones lack resources, training and the assurance that their colleagues are watching their backs. …