Medics took the injured man to Harborview Medical Center with serious injuries, police said.
Seattle police have arrested a man they say stabbed another man on a Lake Washington tour boat late Friday night, police said.
Harbor patrol officers were called to the lake around 9:30 p.m., according to a blotter item posted by police. About an hour later, the agency tweeted police were interviewing witnesses. More than 100 people had been on the boat.
Police said they found a knife and made the arrest. The man was booked into King County Jail for investigation of assault.
Medics took the injured man to Harborview Medical Center with serious injuries, police said. No other information on this condition was immediately available.