Shaikh Abdullah Al-Bukhaari (may Allaah preserve him) stated in Sharh Dawaabit Al-Jarh wat-Tadeel (lesson 1) that Al-Haafidh Ibn Hajr (rahimahullaah) stated in the Muqaddimah of Lisaan Al-Meezaanthat one of the Khawaarij said
O Ahlus Sunnah! Be warned; for indeed when we desire a speech (i.e. desire to hold a view), we device a hadeeth for it (i.e. either fabricate a hadeeth or utilise it in an ambiguous manner).