ZAMBOANGA, Philippines—Motorcycle-riding gunmen killed a town mayor and wounded another in a brazen attack Monday that also killed their driver and caused villagers to flee to safety in a coastal village in the southern Philippines, police said. Mayor Darussalam Lajid of Al-Barka town was killed and Mayor Alih Sali of Akbar town was wounded by at least two men armed with pistols while walking in Zamboanga city shortly after arriving on a speedboat from their island province of Basilan, police said. A bodyguard of the two mayors was wounded and a driver who came to pick them up was killed, police said. Investigators were trying to identify the two gunmen and two companions who escaped on motorcycles and determine their motive, including the possibility that it involved a political rivalry. The two mayors were reportedly running in May 9 elections. Philippine elections have been marred in the past by bloody …