GRANTS PASS — Oregon State Police say a 2-year-old boy is in critical condition and his stepfather is under arrest following a child-abuse investigation.

Police said Saturday that the boy was taken to a Grants Pass hospital by his mother and stepfather and diagnosed with a head injury. He was taken to a hospital in Medford, where he underwent emergency surgery.

The 32-year-old stepfather was arrested on Friday and is expected to be arraigned Monday on charges of assault and criminal mistreatment.