OSAKA -- A head found in Osaka Bay in November has been identified as that of a 45-year-old company president who wasn't reported missing, even by his family, until three months after he vanished, police said Wednesday.

Police are questioning the family of Matsuo Ishitani and employees at his electrical appliance retailer in Osaka on a voluntary basis, because no missing persons report was filed at the time he disappeared around October. They also searched his home as part of a case of abandoning of a corpse.

Ishitani's head was found Nov. 18 floating near an artificial island in Konohana Ward. He was decapitated by a sharp object. The body has not been found.

The head was initially thought to be that of a woman aged between 40 and 60, but later autopsies and examination of the tissue structure showed that the victim was a man. Dental records eventually led to the identification, police said. The time of death was placed at sometime around October.

Ishitani had run the Minato Ward firm, which has several employees, since 1989, according to investigators.

Police said a missing persons report was filed more than three months after Ishitani disappeared, and they are trying to trace his movements before he vanished.