Seven male heads and torsos, along with hands, arms, legs and feet, were found, stuffed in black plastic bags in a house that was being operated as a business, prosecutors said.
Two other men were found riddled with bullets late Saturday in another part of the industrial city, which is located in the state of Coahuila.
Authorities are probing whether the killings were linked to score-settling between rival drug gangs.
President Enrique Pena Nieto was sworn in Saturday as the country’s new leader in a return to power of the Institutional Revolutionary Party (PRI), which ruled Mexico with an iron fist for 71 years.
Outgoing President Felipe Calderon hands on Latin America’s second biggest economy, buoyed by a manufacturing surge, but his six-year term will be mostly remembered for the military offensive against powerful drug cartels, in which at least 60,000 Mexicans lost their lives.
While 25 of the 37 most wanted drug lords were captured or killed, gangland gunfights, decapitations and kidnappings have surged since 2006, with the murder rate almost tripling to 24 homicides per 100,000 inhabitants.