A group advocating for journalistic freedom says a photographer who was found slain in Mexico City had been tortured before his death.

The organization known as Article 19 says Ruben Espinosa sustained severe injuries to his face and was shot twice.

Espinosa was found dead late Friday along with four women. The head of Article 19, Dario Ramirez, says the women also were tortured and showed signs of sexual assault.

Espinosa worked for the investigative magazine, Proceso, and other media. He had fled to the capital in June after being harassed in his home state of Veracruz.

Espinosa's killing has raised tension among reporters who long have considered the city to be a refuge from media intimidation and violence elsewhere in Mexico.