(CNN) -- Police in Hercules, California, were searching Wednesday for a man whose elderly father was bludgeoned to death -- possibly by a suspect in three other homicides in the same area.
The suspect, Efren Valdemoro, was killed in a shootout with California Highway Patrol officers Tuesday night, authorities said. Inside the trunk of his car was the body of a woman, who authorities identified as Valdemoro's girlfriend.
His death marked the end of a bizarre story involving homicides in three cities in the San Francisco Bay area, officials said.
It began with the discovery of the body of 73-year-old Ricardo Sales in his home in Hercules on Saturday, according to a statement from the Hercules Police Department. An arrest warrant was issued for Valdemoro after information came to light that he had had an altercation with the elder Sales and his son the previous week, the statement said.
Frederick Sales, the victim's adult son, has not been located, authorities said, and they fear for his well-being.
"Being an acquaintance of Mr. Efren Valdemoro does not bode well for having a long life," said Hercules Police Chief Fred Deltorchio.
Meanwhile, police in Vallejo, California, were securing a house Wednesday in which the bodies of two elderly women were found, along with a large amount of explosive materials, federal and local authorities said.
Valdemoro is believed to have been associated with both women, said Vallejo Police Lt. Abel Tenorio. The women were last seen August 25, according to a statement from the Vallejo police.
Helen Dunkel, a spokeswoman for the Bureau of Alcohol, Tobacco, Firearms and Explosives, told reporters that the chemicals found in the home could be used to manufacture explosives.
Tenorio said Valdemoro had had some prior "police contact," but not for any violent acts, and he was never arrested or charged with a crime.