The AP reported that the workers, employed by polling firm Consulta Mitofsky, disappeared while working on Michoacán’s upcoming gubernatorial election, in a region plagued by drug-cartel violence.

The firm sent around three dozen pollsters to the area, and when three did not return to their hotel in the city of Apatzingán on Saturday, another three went out searching for them. None have been seen or heard of since.

A kidnapping investigation has been opened. Read the full story here.