Nobusumi was killed because he deemed to have a connection with Mitsuhide since his father, Nobukatsu had a plot to rebel against Nobunaga and he was killed and he was a son-in-law of Mitsuhide.
信澄殺害は、信澄の父・信勝がかつて信長に謀反を企てて殺されている事や彼が光秀の娘婿であった事から光秀と通じていると見なされた事による。