Prosecutors say Joshua Sullivan woke up in the early hours of May 23 to the sound of his crying newborn baby. When he couldn't get the fussy baby back to sleep, Sullivan became frustrated, according to prosecutors.
He picked up the 7-day old and began shaking the boy, causing his head to hit the wall, prosecutors say. In the morning, Sullivan and the baby's mother noticed the infant had two swollen eyes, along with bruises on his face, arms, back and ear.
The couple took him to the hospital, where doctors determined the child had non-accidental head trauma and immediately ordered brain surgery.
The infant's 3-year-old sibling later told authorities that Sullivan got a "mean look" and that "daddy squeezed the baby," according to prosecutors.
"Nothing is more incomprehensible than adults harming children," Pierce County Prosecutor Mark Lindquist said in a Friday news release. "The child is receiving good medical care and appears to be recovering, but we won't know the full effect of this senseless assault for years."
Sullivan pleaded guilty to first degree assault of a child last month, and on Friday he was sentenced to 16 and a half years in prison.