She was murdered by her 21-year-old brother Yuki Muto (武藤 勇貴, Mutō Yūki) (born 1985) on December 30, 2006.
Muto's father and mother were both dentists and she was brought up in a relatively affluent environment, but she was rebellious against her parents and ran away from her home between December 2004 and May 2005.
After her death, the Tokyo District Public Prosecutor's Office denied Yuki's incestuous interest in Azumi,[1] which some tabloids had suspected.
She apparently had told her friends that there were problems in the family regarding her brother's mental state a few days before the murder took place.
[5] On May 12, 2008, prosecutors requested 17 years imprisonment for Yuki, whereas his psychiatrist claimed that he had diminished responsibility or was criminally insane.