Mexico's attorney general's office has launched an investigation into arrests by local officials of eight suspects in the killing of three news photographers in the eastern state of Veracruz, a Mexican official said. 

The official says federal authorities are skeptical of state officials' claims to have solved the case based on confessions. The official spoke Friday on condition of anonymity.

Suspect Juan Carlos Hernandez Pulido was allegedly detained last week with one victim's ID, and local authorities say he led them to the others.

The New York-based Committee to Protect Journalists also has voiced skepticism because of the lack of evidence in the case.

Veracruz State Attorney General Amadeo Flores Espinosa alleges that all the suspects are members of the New Generation gang allied with the powerful Sinaloa Cartel.

Suspect Juan Carlos Hernández Pulido was detained last week with the credential of one victim and led authorities to the others.

Hernández Pulido is allegedly a local chief of informers for the Jalisco Nueva Generacion drug gang, the Mexican navy said. The navy said Hernández Pulido was detained Friday in the Gulf Coast port city of Veracruz as he handed out packets of drugs to a group of men.

The navy said Hernández Pulido was carrying the ID cards of Irasema Becerra, who had been an administrative worker at a local newspaper and was the girlfriend of one of the dead photographers. Five other journalists have been killed in Veracruz state so far this year.

At the time, the May killings had been thought to bear the hallmarks of the hyper-violent Zetas cartel; the victims were slain, dismembered and their bodies stuffed into black plastic bags dumped into a waste canal.

However, Hernández Pulido's alleged links to the Sinaloa cartel, which is fighting the Zetas for control of Veracruz and other states, suggest otherwise.

Based on reporting by the Associated Press.

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