Twelve unsophisticated, low-powered bombs have been found in the past month randomly targeting cars in the city's Irvington neighborhood, police say.
Nine of the bombs have exploded. No one has been hurt. Police have asked for help from the federal Bureau of Alcohol, Tobacco and Firearms.
Police believe there is no connection between the bombs and unemployed crime lab technician Rodney Blach, convicted this month of 11 felony counts, including attempted murder, for planting powerful bombs under the homes of Fremont's police chief and others.