Gunmen assassinated the mayor of a town in the state of Michoacan, west Mexico, as he campaigned on behalf of President Felipe Calderon’s sister 11 days prior to local elections.

State Attorney General Jesus Montejano said that four individuals opened fire on the mayor of La Piedad, Ricardo Guzman Romero, as he and fellow party members distributed flyers for PAN (Partido Accion Nacional – National Action Party) candidates.

The candidates included Maria Luisa Calderon, sister of Mexico’s current president, who is running for governor of the state of Michoacan.

In August, a mayor in the neighboring state of Guerrero was kidnapped and killed. Romero is the 20th mayor assassinated in Mexico since 2010, according to reports.

Michoacan is the home state of drug gang the Familia Michoacana and offshoot the Caballeros Templarios.