RedactedNarrative: Sgt. responded to Everett Ave in Westerly, RI for a report of a swimmer who was struck by a boat.  The swimmer, Victim was being transported to Westerly Hospital for a broken left shoulder and lacerations to his left arm caused by the boat propeller. EPO who was also at the scene stated that Victim was swimming about 3/8 – ½ mile off shore doing the backstroke in an east-northeast direction when he was struck by a boat travelling west.  Victim reported the boat stopped briefly about 100 yards away and then left the area continuing west.  Sgt. and EPO viewed security video filmed from a nearby private residence and the Ocean House hotel with negative results.  None of the cameras were able to capture the accident.  The following day a witness contacted DEM headquarters and stated that he had an encounter with a swimmer in that same area the day before the accident.  Sgt. spoke with the witness who stated that he was fishing in the area when a swimmer who was doing the backstroke approximately ½ mile off of East Beach in Westerly.  He saw the swimmer’s arm come up through the water otherwise he would have never have seen him.  He stopped and told the swimmer it was dangerous swimming in that area and that he almost hit him.