Mexican security forces found 49 decapitated and dismembered bodies in a roadside ditch near Monterrey, the capital of Nuevo Leon state, authorities said Sunday. The bodies were accompanied by a note signed by the Zetas drug cartel, dpa reported. The bodies had been dumped in the early hours in an uninhabited area in the Cadereyeta municipality, a spokesman for Nuevo Leon state, Jorge Domene, told a press conference. "To complicate the identification, none of these people was found with a head, and their (arms and legs) were mutilated," Domene said. Of the 49 bodies, six were women and the rest were men. Some bodies were in plastic bags and many were naked. Authorities were hoping to identify some of the victims by their tattoos. The Monterrey deaths constitute the third mass killing in nine days in northern Mexico. Twenty-three men were killed near the US border in Nuevo Laredo at the start of the month, and last week police found 18 dismembered bodies in the state of Jalisco. Police believe the deaths are related to heightened rivalries between drug cartels, particularly the Zetas and the Gulf Cartel. The most recent deaths are thought to be revenge attacks following the Nuevo Laredo killings. A further six bodies were found in three different locations in the state of Sinaloa, officials said earlier Sunday.