Mexican newspaper editor Maria Macias found decapitated
Prosecutors in Mexico say the decapitated body of a woman found in the northern city of Nuevo Laredo on Saturday is that of a newspaper editor.
The body of Maria Elizabeth Macias, the editor of Primera Hora newspaper, was found next to a threatening message.
The police said the message had been left by a criminal gang.
Two weeks ago, the bodies of a man and a woman were hung from a bridge with a message warning people not to report drug violence on social networks.
Ms Macias' body was found early on Saturday in a busy area of Nuevo Laredo, in northern Tamaulipas state.
A message left next to her remains accused her of denouncing drug violence on social networks and websites, such as Nuevo Laredo en Vivo, or Nuevo Laredo Live, where citizens can leave messages pointing the security forces to the locations where gangs congregate and sell drugs.
A message left on a pedestrian bridge in Nuevo Laredo from which two people were strung up on 13 September also warned people not to report crimes on such sites.
That message had been signed with the letter "Z", usually associated with the Zetas cartel.
Tamaulipas has been at the centre of a bloody turf war between the Zetas and their former allies turned bitter rivals, the Gulf cartel.
Beheadings have become a common feature of many murders carried out by the Zetas, aimed at terrorising rivals and those who they consider snitches.
The US-based journalists' welfare group Committee to Protect Journalists says 59 journalists have been killed in Mexico since 1992.
It says 25 of those were murdered in direct reprisal for their work.