A prominent activist with Mexico's Movement for Peace, who joined the campaign after the disappearance of his son, has been assassinated in the northwestern state of Sonora.
Nepomuceno Moreno Nuñez, known as "Don Nepo," was shot at least seven times by an unknown assailant while driving in downtown Hermosillo.
Don Nepo reportedly contacted Javier Sicilia, who leads the Movement for Peace, for assistance in finding his son, who disappeared after being arrested by police in Ciudad Obregon, Sonora.
The state prosecutor general said that organized criminal groups were thought to be involved in the killing.
The Movement for Peace has gained traction in recent months, leading large-scale protest marches across the country, and President Felipe Calderon has met with Sicila to discuss the group's criticisms of his crime policies.