ST. HELENS, Ore. - A St. Helens father has been charged with seriously injuring his 5-month-old son, authorities said.

Hipolito Guzman Salizar, 28, is facing charges of first-degree assault and first-degree criminal mistreatment. He was being held on $170,000 bail at the Columbia County jail.

According to St. Helens police, the boy was admitted into Legacy Emanuel Hospital in Portland on Nov. 26 for treatment of the head injury. Medical professionals and investigators determined the injuries were caused by abuse and were consistent with a violent shaking.

Detectives determined the assault occurred in the child's home and began to investigate the family. On Monday, St. Helens police interviewed and arrested Salizar in connection with the abuse.

The child was listed in serious condition at the Hospital Tuesday. Police said the extent of his injuries remained unknown until hospital officials could conduct more tests.