Sheriff's investigators think that the same person is responsible for two mailboxes that were blown up in four days in a Diamond Bar neighborhood.
The most recent explosion happened about 10 p.m. Monday at 23459 Coyote Springs Drive, said sheriff's spokeswoman Britta Tubbs.
The wooden mailbox, which was about 25 feet from the house, was destroyed by an acid bomb. The blast was caused by a chemical reaction.
The same type of bomb was used to blow up a mailbox at another home in the neighborhood, at 23322 Forest Canyon Drive, Friday night, Tubbs said.
It was unknown why the two mailboxes were targeted.