EVERETT, Wash. -

A Marysville man has been charged with child assault after allegedly breaking his 4-month-old son's arm.

The Everett Herald reports 26-year-old Robert Okerstrom was arrested in July shortly after the child was taken to a Seattle hospital. A doctor there had concluded the broken arm was "highly suspicious."

Prosecutors say Okerstrom allegedly admitted bending the baby's arm behind his back while in a "fit of rage." He reportedly told a detective that he thought he might have hurt the child but, upon checking the baby's arm, "didn't think anything was wrong or worthy of medical attention."