Five severed heads and their bodies were dumped in two spots Saturday morning around the capital of the western state of Michoacan that has been plagued by worsening drug gang violence this year.
Three sets of bodies and heads were displayed in the street in a township on the northern edge of Morelia and the other two were left in the town square of a community in the southern part of the capital, according to a statement from the state prosecutor's office.
Michoacan's murder rate rose in 2013 compared to declines in most states. Last month, dozens of mutilated corpses were found buried in mass graves in an area on the border between the states of Michoacan and Jalisco.
Nationwide, murders peaked in 2011 amid a military-led war against drug gangs, official data shows.
President Enrique Pena Nieto, who ends his first year in office, shifted focus away from battling drug cartels to pushing a series of economic reforms through a divided Congress.
Violence spiked in Michoacan in recent years and masked groups of vigilantes took power in some rural communities in 2013, claiming the government was failing to stop gang extortion and violence.
Michoacan's murder rate has nearly doubled since 2006 as traffickers increasingly turned from marijuana plantations to producing methamphetamine in crude labs hidden amid the state's mountains and avocado groves.
Decapitations became an increasingly common form of gangland vengeance across Mexico since five heads were tossed onto a barroom dance floor in the Michoacan town of Uruapan in 2006.