EVERETT — Prosecutors on Friday filed an assault charge against the father of a 5-week-old boy who suffered multiple broken bones, including 15 fractured ribs.

Doctors concluded that the boy’s injuries were consistent with child abuse. Andre Ashe allegedly told detectives he shook the baby because he wouldn’t stop crying. He also reportedly admitted that he hit the baby’s head against a wall, Snohomish County deputy prosecutor Katie Wetmore wrote in court papers.

In addition to the broken ribs, the infant had a fractured skull and a broken arm and leg. The rib fractures were in different stages of healing. Doctors told detectives that the injuries likely happened over a 10-day span.

The doctors reported that it didn’t appear that the boy suffered any neurological damage. They predicted that he would make a full recovery.

Ashe, 33, was charged with second-degree assault of a child. He is being held on $250,000 bail.

Prosecutors allege that the boy’s injuries were severe and he was particularly vulnerable. They also allege that Ashe abused his position of trust. That leaves the door open for a more severe punishment if Ashe is convicted.

The boy’s parents agreed to bring him to the Everett Clinic in Mukilteo on March 14 after his grandmother noticed a lump on his head. The boy’s mother was on home detention so Ashe and the child’s grandmother took him. Doctors quickly determined that the boy needed to go to Children’s Hospital in Seattle.

The boy’s mother told a Mukilteo police detective that she didn’t know how the boy had been injured. She said Ashe had worked all day and then stayed up with the baby while she slept. She said Ashe had been awake for about 26 hours.

A few days later Ashe agreed to take polygraph test at the Everett Police Department. He became emotional and started to cry. He reportedly told detectives that he had shaken his son the night before he was taken to the hospital. He admitted that it wasn’t the first time he had done that, Wetmore wrote.

He said one time he lost his grip on the boy and grabbed him by the leg. He also admitted to squeezing the boy, court papers said.

Diana Hefley: 425-339-3463, hefley@heraldnet.com. Twitter: @dianahefley