City News Service reports 26-year-old Joshua Allen Robey of Costa Mesa was convicted Monday and faces 15 years to life in prison at his Sept. 27 sentencing.
Robey's girlfriend caught him abusing the child in October 2011 after she set up a hidden camera in her home to see if he was cheating on her. Instead she saw video of her boyfriend abusing their son including covering the child's nose and mouth with tape.
The girlfriend's mother took the infant to the hospital where staff contacted police.
The baby suffered fractured ribs, brain hemorrhaging and liver injuries.