Police are investigating the death of a 17-year-old boy who was last seen by his friends in a motorized dinghy in Newport Harbor. The body of Theodore Oliveira was found Monday morning floating near the Pell Bridge. Captain Russell Hayes told The Newport Daily News that investigators are not ruling anything out, and are looking into whether it was a crime or an accident. Oliveira was last seen alive on Aug. 27 around 11 p.m. Police said he was on one dinghy and two friends were on another before he disappeared. He was reported missing the evening of Aug. 28.