State Attorney General Amadeo Flores Espinosa says all the suspects are alleged members of the New Generation gang allied with Mexico's powerful Sinaloa Cartel led by fugitive Joaquin "El Chapo" Guzman.
Flores said Wednesday that the suspects also are accused of other crimes.
Three photographers and the girlfriend of one were found May 3 dismembered in garbage bags in sewage canal.
Suspect Juan Carlos Hernandez Pulido was detained last week with the credential of one victim and led authorities to the others.
Sinaloa is in a fierce battle with the Zetas for the port city of Veracruz.