On October 28, only three days after Niimi's death, Serizawa and Goro HIRAYAMA from the Mitoha group were attacked and murdered by the Shieikanha group, by which the Mitoha group of Shinsengumi was destroyed.
新見の死の僅か3日後の9月16日に芹沢と水戸派の平山五郎が試衛館派に襲撃・暗殺されており、新選組の水戸派は壊滅した。