Officials have not released any information on the identity of the dead or the circumstances of the killings. The public display of victims is characteristic of Mexico's drug cartels and other criminal outfits.
Gabriela Muñiz, the jailed leader of a kidnapping gang, was found hanging from a bridge in the northern city of Monterrey just days after armed men snatched her from prison guards as they were taking her to a hospital.
While in Tijuana, next door to San Diego, California, killers left the naked, battered body of a state official hanging from a bridge. Sinaloa, the birthplace of Mexico's first generation of drug lords, is among the states hardest hit by a conflict pitting cartels against each other and the security forces that has claimed nearly 35,000 lives nationwide in the past four years.
The state is the bastion of the Sinaloa cartel, whose leader, Joaquin "El Chapo" (Shorty) Guzman, remains at large more than a decade after escaping from a maximum-security prison.