A Navy man is charged with assaulting a 3-year-old child and causing a life-threatening internal injury, court documents state.

The suspect is also being investigated in connection with an infant’s injuries.

The baby sustained a depressed skull fracture, according to the Island County Prosecutor’s Office.

Jason L. Gaines, 21, of Oak Harbor, was arrested Nov. 8 by Oak Harbor police for allegedly assaulting his stepson.

Gaines pleaded not guilty in Island County Superior Court Nov. 18 to assault of a child in the first degree, a domestic violence crime.

The 3-year-old boy was transported to Children’s Hospital in Seattle Nov. 5 after being diagnosed at the Navy hospital with possible appendicitis.

Doctors, however, found that the boy suffered from a ruptured spleen.

The force needed to cause the injury was equivalent to the “force often seen resulting from a body impacting a steering column in a motor vehicle accident,” Detective Manuel Silveira wrote in a report on the incident.

The boy told a doctor that his “daddy” hurt him.

The child later told investigators his dad hit him on the “tummy” when his mother was at work, the detective wrote.

On Nov. 12, Judge Alan Hancock released Gaines on his own recognizance, allowing him to live in Navy barracks. He also allowed Gaines contact with the alleged victim, in accordance with the outcome of an earlier shelter care hearing.

During the shelter care hearing, Gaines said he was roughhousing with the child, but didn’t know if that caused the injury.

Senior Deputy Prosecutor Eric Ohme made a motion to amend the conditions of release to prohibit Gaines from contacting either the 3-year-old boy or 5-month-old baby.

The baby lives in the same household.

The baby underwent a CT scan and was diagnosed with a skull fracture.

During a Nov. 18 hearing, Judge Vickie Churchill ordered Gaines not to have contact with either child.