RedactedNarrative: On 08/08/15, Subject beached his boat on a sandbar located on the west side of the Kaskaskia River approximately 1.5 miles south of the IL Rt 177 Bridge.  Victim dove off of the back of the boat into the river headfirst.  Subject1 said he saw Victim surface briefly, then go back under the water.  He said he thought Victim was messing around in the water and had drifted around the point to where he could not see him anymore.  A few minutes later, Operator began operating down river looking for Victim.  After going down river for quite a distance, he realized Victim would not have made it that far down and went back up to the original area thinking Victim might be on shore somewhere.  After looking in the area and calling for him, they were unable to locate Victim.  They then called 911.  
  
  CPO''s and I responded to the area and began a surface search.  Other volunteer agencies came to assist.  Side scan sonar was used, but was not successful in locating Victim.  
  
  The search continued until 08/09/15 at 0200 hours.  It resumed on 08/09/15 at 0900 hours, went all day long, again, with no success in finding Victim.  On 08/10/15 at approximately 1135 hours, Victim was found approximately 3/4 mile down river from where he had went in by friends of Victim.  CPO''s were contacted who came and took custody of Victim'' body.  Clinton County Coroner was contacted and he came to the scene to take custody of Victim'' body.  
  
  After interviewing Operator and Occupant1, their stories were consistent.  Victim had been on another boat approximately 15 minutes prior to them stopping on the sandbar. Victim decided to come onto their boat and when they stopped at the sandbar, Victim said he was going for a swim. Operator said he heard Victim jump off of the boat, but didn''t see him due to the fact he was watching his son, who had went on shore to go to the bathroom.  Occupant1 said he saw Victim jump off of the boat head first into the water.  He said a couple of seconds later, he saw what he thought was Victim'' back come up almost to the surface.  He said it looked as if Victim was floating to the surface and then trying to swim back under the water.  He did not see Victim come back up, and thought he may have drifted down river and around the point where he could not see him.  He told Operator this, so they motored down river in attempts to find him.  After going down river for approximately 1 mile, they were unable to find him and they turned around and went back to the place Victim jumped in.  The both said they thought he was on shore somewhere near there and would be waiting for them.  After not finding Victim, Occupant1 called 911.
  
  Coroner said Victim had some edema in his neck that was visible during an X-Ray.  However, the family did not want an autopsy to be conducted.  The preliminary cause of death was drowning.