SAN FRANCISCO (AP) - Police in San Francisco say they're investigating a sexual assault allegation involving 49ers wide receiver Michael Crabtree.

Police said in a statement released Friday night that the alleged assault occurred in a city hotel room early Sunday.

The statement says Crabtree has been interviewed with his attorney present and has cooperated with the probe. The receiver hasn't been detained or arrested, and agreed to be available for further questions in the future.

Authorities didn't release any further details, and a spokesman for the 49ers had no immediate comment.

San Francisco is preparing to play the Atlanta Falcons in the NFC championship game on Sunday. The winner goes to the Super Bowl.