Nuribe no miya tsukokimitari and Nakatomi no miya konomuraji azumahito got secret information that 'Prince Nagaya was led into the wrong course and wished to subvert the state', so the troops of rokuefu (six guard divisions) led by FUJIWARA no Umakai besieged the residence of Prince Nagaya and, as a result of inquiries by Imperial Prince Toneri and others, Prince Nagaya ordered to strangle his empress Imperial Princess Kibi and his son Kashiwade no Okimi to death and killed himself with poison.
神亀6年（729年）2月、漆部造君足（ぬりべのみやつこきみたり）と中臣宮処東人（なかとみのみやこのむらじあずまひと）が「長屋王は密かに左道を学びて国家を傾けんと欲す。」と密告があり、それをうけて藤原宇合（ふじわらのうまかい）らの率いる六衛府の軍勢が長屋王の邸宅を包囲し、舎人親王などによる糾問の結果、長屋王はその妃吉備内親王と子の膳夫王らを縊り殺させ服毒自殺した。