BERLIN: Authorities say the skull of the director of 1920s silent vampire classic "Nosferatu" has been stolen from his grave in Germany.

Olaf Ihlefeldt, the administrator of the cemetery in Stahnsdorf, outside Berlin, said the theft of Friedrich Wilhelm Murnau's skull was noticed Monday. He said Wednesday it's hard to pin down when it was stolen but the theft likely took place between July 4 and 12.

It wasn't clear whether Murnau was targeted specifically, and the thief or thieves left little superficial damage. He is buried alongside his two brothers, whose graves were undamaged.

Police opened an investigation and called for witnesses who may have seen anything suspicious at the cemetery over recent weeks to come forward.

Murnau died in a road accident in Santa Barbara, California, in 1931.