Superintendent Pastor de Guzman, city police chief, said councilor Artemio Gomez Jr., 57, died from a gunshot wound in the head.
His brother, Rene, 44, was in critical condition due to multiple gunshot wounds.
The police said the Gomezes were tending their garden in their frontyard in Barangay Balibago at about 8:10 a.m. when they were attacked.
Three empty shells of a 9-mm pistol and a deformed caliber .45 slug were found at the crime scene.
Witnesses said the gunmen escaped on board a tricycle after the gunslaying. — With Ed Amoroso