The family pets were not boy's best friend last week.
Police arrested a 12-year-old in the Central Valley town of Atwater on Friday, after he allegedly killed two of his foster father's Chihuahuas and injured a third dog.
San Joaquin Valley investigators say one of the dogs tried to bite the boy so he threw the animal down an irrigation pipe near his home on Friday. He then threw the other two dogs down a smaller pipe, tossing a chunk of cement on top of them, and they drowned.
The dog thrown down the larger pipe washed out into a canal and returned home.
Merced County sheriff's Deputy Tom McKenzie says the boy was arrested and taken to Juvenile Hall.