The bodies of two reporters were discovered Thursday behind a Mexico City cemetery, prosecutors said.
The Mexico City justice department said both women's clothes had been stripped off and their hands and feet were tied, the Los Angeles Times reported. They were identified as Ana Marcela Yarce Viveros, one of the founders of the news magazine Contralinea, and Rocio Gonzalez Trapaga, a former reporter for Televisa, who was said to be a freelancer.
The two women were old friends and met for coffee Wednesday night, friends said.
Investigators said the motive for the killings was unclear. While human rights groups say at least 60 journalists have been killed during the five years of drug violence, Mexico City has generally been regarded as a safe place to work.
"This violence is reaching all Mexicans … including journalists," Miguel Badillo, the editor of Contralinea, told an interviewer. "A terrible crime."