Mexican authorities say two female journalists were found murdered south of Mexico City Thursday.

They say the women's bodies were found in a park in Iztapalapa south of the capital.

One victim is Ana Maria Marcela Yarce Viveros, founder of investigative magazine Contralinea.

The second, is Rocio Gonzalez, who used to work for broadcaster Televisa.

Reuters news agency says a Contralinea spokesman says both women were naked with their hands and feet tied.

Authorities believe they were strangled, but the exact cause of death has not been released.

Dozens of journalists have been killed in drug related violence in Mexico in the past five years, but investigators have not given a motive for the murders of the women.

More than 40,000 people have been killed in drug related violence in Mexico since President Felip Calderon launched a national crack down on drug cartels in 2006.