Mercer Island police marine unit is looking for a 19-year-old who went into Lake Washington on Friday night and has not been seen since.
According to police, the 19-year-old was last seen on July 31 around 10:40 p.m.
He was on a boat watching Seafair events, and told his friends he needed to go to the bathroom. Mercer Island PD said the boat was in motion at the time, between Seattle and Mercer Island, and may have been traveling at “planing speed.”…