Sumitomo was connected with a series of these incidents because 藤原三辰, the former Yamashiro no jo (an official of Yamashiro Province), was the senior commander of Sumitomo's army, and also because, ever since his attack on FUJIWARA no Sanetaka as mentioned above, his influence had become prevalent amongst not only pirates of the Seto Inland Sea, but also armed discontented elements, or 'robbers', based in the area between Heian-Kyo (the ancient capital in present-day Kyoto) and Settsu Province.
なお、この一連の事件と純友との関係について純友軍の幹部に前山城掾藤原三辰がいる事や先の藤原子高襲撃事件などから、実は純友の勢力は瀬戸内海のみならず平安京周辺から摂津国にかけてのいわゆる「盗賊」と呼ばれている武装した不満分子にも浸透していた。