A Oaxaca state legislator, who was also a teacher and mayor-elect of the city of San Andres Cabecera Nueva, was gunned down while eating at a restaurant, Mexican prosecutors said Wednesday.

Everardo Hugo Hernandez Guzman, a member of the leftist Party of the Democratic Revolution, or PRD, was killed by a lone gunman who "shot him twice in the head and arm," the Oaxaca Attorney General's Office said.

The 53-year-old Hernandez Guzman was murdered around 10:40 p.m. as he was dining at a restaurant in the city of Santa Cruz Xoxocotlan, the AG's office said.

Investigators found two bullet casings from a 9 mm weapon at the crime scene.

The PRD's spokesman in Oaxaca, Fidel Ernesto Lopez Nelio, condemned the murder in a Twitter posting and said the leftist party and the state legislature "lost a comrade who was reliable, important and loyal to his convictions."

Oaxaca Gov. Gabino Cue also condemned Hernandez Guzman's killing and vowed to investigate the case "fully and to bring those responsible to justice."

Investigators have "not ruled out any line of investigation," the AG's office said. EFE