The cadavers are unclaimed "and there are no reports of people missing in the area," a source in the office of the Michoacan attorney general told AFP yesterday.
Assailants left the severed bodies in the car on the outskirts of the municipality Venustiano Carranza in Michoacan, near that state's border with Jalisco.
While the perpetrators have not yet been identified, prosecutors said in an official report that authorities had spotted a suspect taxi that was followed by a dark vehicle entering the town of La Barca in Jalisco en route to Michoacan.
Michoacan and Jalisco are hotbeds of drug production and trafficking to the United States. Assassinations and bloody clashes between cartels are commonplace in the region.
In 2013 ,farmers in Michoacan formed militias to defend themselves against the now disbanded Michoacan Family organized crime syndicate and its offshoot cartel the Knights Templar, criminal organizations known for extortion, kidnappings and murder in the area.