5 Killed in Attacks on Mexico Police
Investigators say assailants threw a grenade and fired on a police station, killing a doctor and two officers inside the facility.
Guadalupe is also in Nuevo Leon, which has seen violence as rival drug cartels fight over lucrative smuggling routes.
About 30,000 people have been killed in Mexico's drug war since President Felipe Calderon took office in late 2006 and began cracking down on the cartels.