Fond du Lac police are investigating a domestic violence incident that sent two men to the hospital early Monday.Officers said they responded just after 2 a.m. Monday to a residence in the 100 block of East 1st Street, where a 2 0-year-old man had stabbed his 46-year-old father during an altercation.Police said the son allegedly stabbed his father multiple times after being attacked with a hammer. Both men live at the residence.The father suffered multiple stab wounds, according to police. Officers provided medical aid until Fond du Lac Fire Rescue arrived. He was airlifted to a regional medical center, where he underwent surgery and is listed as stable.The son sustained minor injuries and was transported to a local hospital, where he was admitted for additional care and is also stable.Detectives are actively investigating the circumstances, police said. ...read more read less