According to roomates of the victim he decided to take a friend's inflatable boat with an electric motor out onto the lake with the intend to go swimming.  He did this on many afternoons after work.  A passing officer saw a boat adrft and appeared to be unoccupied.  Occupants of a local taven flagged down the officer and stated they saw the victim jump/fall (conflicting witnesses) into the water.  This lake was full of vegetation, very murky and had a layer of sediment on the bottom.  One of the rescue swimmers himself became entangled in the vegetation and had to be assited to shore.  He was found 4 days latter and had died.  His roomates said he was a very strong swimmer.  The vessel was not anchored.  It is felt by the officer that the victim became entangled in vegetation and died.