MEXICO CITY — A state assembly candidate in the southern Mexican state of Guerrero was killed just days after another office-seeker was shot to death in the same city, authorities reported.

The ruling Institutional Revolutionary Party said candidate Dulce Rebaja Pedro was killed Sunday.

The Guerrero state prosecutors' office said a state policeman was also killed, and both bodies were found in a truck on a highway outside the city of Chilapa.

On Monday, state security spokesman Roberto Alvarez reported that Rebaja's aunt was also found dead in a well at her son's home.

Antonia Jaimes Moctezuma, a state assembly candidate for the leftist Democratic Revolution Party, was shot to death last week.

Chilapa is one of the most violent cities in Mexico because of a turf battle between two local drug gangs.

Violence threatens to mar local races that are being held simultaneously with Mexico's July 1 presidential elections.