When that student attacked an officer of the Japanese Self-Defence Force in Asaka, Saitama, killing him, Kawamoto was arrested for spoliation of evidence.
Saat pelajar tersebut menyerang seorang perwira Angkatan Pertahanan Diri Jepang di Asaka, Saitama, membunuhnya, Kawamoto ditangkap atas dakwaan penghilangan barang bukti.