Tokyo police searched the headquarters of a Yamaguchi-gumi underworld affiliate Tuesday in connection with the arrest the previous day of its boss for allegedly illegally transferring the property rights of a building in Shibuya Ward.

The headquarters of the Goto-gumi in Fujinomiya, Shizuoka Prefecture, was raided by Metropolitan Police Department investigators as well as the Tokyo head office of Ryowa Life Create Co., a real estate agent listed on the second section of the Tokyo Stock Exchange.

Police arrested 10 people Monday in connection with the illegal transfer of the property rights of the Shibuya Ward building. Tadamasa Goto, 63, head of the Goto-gumi, and Susumu Nishioka, 52, president of Ryowa Life Create, were among those collared.

Police alleged the suspects transferred the property rights of the building to a company affiliated with the Goto-gumi in February 2005 without the consent of the owner.

The 12-story building, located in the Yoyogi district, is two-thirds owned by a family-run real estate company and is worth about 2 billion yen.

Police plan to investigate whether the case is connected with the murder in March of Kazuoki Nozaki, 58, a consultant for the family-owned realtor who was in charge of clearing out people illegally occupying the building.

The arrests and Tuesday's searches were prompted by suspicions that the suspects violated the Penal Code, which prohibits giving false information on official documents. If convicted, they could face up to five years in prison or a fine of up to 500,000 yen.

The Goto-gumi is affiliated with Japan's largest underworld syndicate, the 22,000-member Yamaguchi-gumi, based in Kobe.