Outraged Mexican journalists say Veracruz state officials have prematurely declared that a reporter found slain this week was killed in a personal vendetta.

They point to the fact that Gregorio Jimenez's body was discovered alongside the corpse of a union leader whose kidnapping was the topic of two of the reporter's stories.

Jimenez is at least the 12th journalist slain or missing since 2010 in the Gulf state.

Prosecutors have arrested five people in connection with his killing, which they attribute to a dispute with a neighbor prompted by a spat between their young adult children.

But Jimenez was found alongside union leader Ernesto Ruiz Guillen, who was kidnapped in January. Jimenez wrote two stories about Ruiz before he himself was kidnapped last week by masked gunmen.