OMAHA - A 12-year-old boy has been charged with first-degree sexual assualt after he was accused of raping a 12-year-old girl at an Omaha elementary school during summer session.

Prosecutors charged the boy on Friday.

A police report says the rape occurred July 2 at Pinewood Elementary School, which is in north-central Omaha.

The girl reported that the boy followed her into the girls' bathroom. She said he threatened her with a knife, but police have been unable to confirm that account.

The girl also said the boy warned her not to tell anyone about what happened.

The boy was arrested on Tuesday, and he remained jailed on Friday at the Douglas County Youth Center.