In 1099, an incident occurred in which his servant on guard had deprived of the criminals by their accomplices (according to "Gonijo Moromichi ki" (Diary of FUJIWARA no Moromichi)).
康和元年（1099年）に俊信の従者が罪人を仲間に奪われるという事件が発生している（『後二条師通記』）。