(Portland, OR)  --  Police say a body found in the Columbia River near Sauvie Island is that of a swimmer who went missing last week.  The Multnomah County Sheriff's Office says someone found the body yesterday on the shore at Willow Bar.  Police say the swimmer went missing near Reeder Beach last Friday after falling off his flotation device and disappearing beneath the water's surface.  Police are working to notify the swimmer's family before releasing his identity.