Man convicted of killing 9-month-old baby

Alexander Lucas Barnes, 20, was convicted of killing his girlfriend's 9-month-old son by repeatedly hitting the child's head against a wall to make him stop crying.

Barnes was found guilty of second-degree murder and child abuse resulting in death. He faces a maximum sentence of 25 years to life in state prison and will be sentenced in January.

Barnes was baby-sitting Isaiah Prim-Ortiz while his girlfriend attended class at a community college. According to a news release from the Orange County district attorney's office, Barnes inflicted "blunt force trauma" on the baby to quiet the child before placing him back in his crib.

The mother arrived shortly after 1 p.m., and noticed that the child was not breathing. The child died in the hospital shortly after 4 p.m. due to multiple skull fractures inflicted by Barnes.