Coroner's officials released the name and cause of death Friday of an 8-month-old boy who authorities said was killed by a Washington man his mother was dating.

Baron Brian Smith was assaulted and died of multiple injuries in Tehachapi, and his death is a homicide, according to a coroner's office release. Authorities were dispatched late Monday to an apartment in the 600 block of Cherry Lane, where they found his body.

Baron was in the care of Tobin Phillips, 20, when he was killed, Kern County sheriff's officials said. Phillips is charged with first-degree murder and is being held on $2 million bail.

According to court documents, Phillips told investigators he covered Baron's head with a pillow to get him to stop crying. He then sat on the pillow until the boy lost consciousness, the documents said.

Afterward, Phillips shook the boy, striking the child's head repeatedly on the metal bar of a futon, the documents said. He poured a cup of water on the child' s face as he tried to revive him, and splashed hot water on him in what he told investigators was an effort to "shock" the boy awake.

Phillips fled the apartment before deputies arrived, but was taken into custody at a Fastrip on Tucker Road two hours later.

Authorities say this is the second time in two months Phillips has injured a child.

In November, he was arrested in Albion, Wash., in connection with assaulting his 21-day-old daughter. Prosecutors there said the baby was "seriously injured" and has been placed in protective custody.

The baby is expected to make a full recovery, prosecutors said.

Phillips had been released on his own recognizance pending a future court date when he traveled to Kern County and committed the second assault, according to authorities.