CEDAR CITY — Police have arrested a 12-year-old boy on investigation of child rape, one of the youngest sex offender cases authorities have dealt with.

"If it's not the youngest, it's close," Cedar City Police Sgt. Jerry Womack said Monday.

Police said the boy sexually assaulted a 7-year-old girl over the course of a year. The girl disclosed the alleged abuse to her mother, who contacted the Division of Child and Family Services.

DCFS caseworkers then contacted police. Officers arrested the boy on investigation of rape of a child; sodomy on a child, both first-degree felonies; and sexual abuse of a child, a second-degree felony.