The identity and cause of death of a man found Thursday afternoon floating in the Columbia River, about ten miles south of Mattawa, is under investigation by Grant County authorities. Grant County Sheriff Tom Jones reports that officials received a 9-1-1 call around 2-30p.m. after citizens found a body east of the Vernita Bridge. Jones says other witnesses told investigators the m an had been seen earlier that afternoon with a kayak. The Sheriff says detectives found no evidence of foul play and they believe they know who the man is.