The injuries were discovered when the little boy's mother took him to the hospital for an examination. The mother said she noticed that the baby's arm was red, swollen and limp and that he let out a "blood-curdling scream" when she touched it after the boy's father had been taking care of him.
The examining doctor told police that the baby's broken arm was broken in two places between the elbow and shoulder and "most likely was caused by a forceful bending motion," according to court documents.
The leg fractures were "caused by twisting and turning commonly found in child abuse," the doctor told investigators. The doctor also said the fractures were "not consistent with normal playful activities," court documents say.
The suspect, identified as Robert Okerstrom, 26, was questioned by police about the boy's injuries.
He initially said he may have accidentally hurt the boy when he took him from his car seat and admitted that he heard the little boy's arm "pop." He also said he may have accidentally squeezed the little boy too hard while feeding him his bottle.
Under continued questioning, Okerstrom finally admitted he had broken the baby's arm in a "fit of rage" by bending his arm behind his back while removing him from a car seat, according to court documents.
Okerstrom also admitted he was most likely responsible for the fractures in the baby's legs, but downplayed the cause, saying he was only playing with the boy, court documents say.
Okerstrom was then booked into Snohomish County Jail for investigation of three counts of second-degree child assault.