Four unidentified gunmen on motorcycles shot and killed Bedoya, a regional correspondent for the Bogotá-based Communist Party newspaper Voz, as he stepped off a bus in the southwestern port city of Tumaco, police and colleagues said.
Bedoya, 52, had worked for Voz for about a year and a half, according to Alvaro Angarita, one of the weekly's senior correspondents.
Angarita linked the murder to a series of highly critical reports that Bedoya had published about collusion between security forces and right-wing paramilitary gangs in Nariño Department. Police confirmed the killing but gave no further details.
Southwestern Colombia, especially Nariño Department and neighboring Cauca Department, experienced a number of paramilitary attacks in the two months before the killing.
Colombia's small Communist Party has political links to the left-wing guerrilla organization Revolutionary Armed Forces of Colombia (FARC), but has traditionally advocated social change through grassroots mobilization and the ballot box rather than armed revolution.
CPJ published a news alert about the Bedoya murder on May 14.