Rodolfo Rios Garza

Rodolfo Rios Garza says the person was identified by a fingerprint found in the apartment and that it registered to someone with a criminal record.

Photojournalist Ruben Espinosa was found dead Friday, shot in the head, his body bound and tortured. The attackers also killed his friend, Nadia Vera and two of her roommates, as well as their 40-year-old housekeeper.

Espinosa had fled the state of Veracruz after being threatened and harassed by strangers.

But the killings may have had to do more with the four women found dead alongside Ruben Espinosa, 31, who worked for the investigative magazine Proceso and other media, Mexico City prosecutor Rodolfo Rios Garza said in news conference.

Rios did not identify the other victims, only giving their ages as 18, 29, 32 and 40. All were shot in the head with a 9 mm weapon. He said they are focusing on the crime as a feminicide, though they have not discarded other motives.