A Waterloo man who was stabbed on Friday night has now been arrested for Domestic Assault, according to the Waterloo Cedar Falls Courier. 42 year old John Smith IV was allegedly assaulting a woman in a bedroom around 11:45 Friday night when the son heard the commotion, kicked the door open, and stabbed Smith. Smith was taken to MercyOne Waterloo Medical Center. The son was not charged. Smith, however, was charged with second offense Domestic Assault. He was also on unsupervised probation for punching another woman in May.