RedactedNarrative: This incident occurred July 20, 2021, approximately 4 hours into a drift boat fishing trip on the Snake River led by fishing guide OPERATOR 1.  PASSENGER 1 was in the front of the boat and VICTIM was in the back.  While paddling downstream, GUIDE entered the tongue of a rapid and asked PASSENGER 1 to brace while standing and center his knees into the front of the drift boat because he felt the eddy of the river pulling on the back port side of the boat.  VICTIM was sitting at the rear of the boat fishing and perhaps was putting her weight on the port/left inside of the boat with her feet on the side wall of the boat.  Water came over the back port side wall of the boat and instantly started to fill the boat with water. GUIDE tried to push with his right oar (2 strokes) to see if he could reposition the boat out of the eddy, but he was unsuccessful and the boat capsized and all three occupants fell into the river.  
  PASSENGER 1 and VICTIM were both wearing NRS inflatable, belt-style PFDs, which had been provided to them by GUIDE, when they entered the water.  PASSENGER 1 tried repeatedly to inflate his PFD but it did not work, so he removed it and swam to shore.  PASSENGER 1 and GUIDE made it to shore but could not locate VICTIM.  Anglers in another drift boat saw VICTIM floating in the river and were able to recover her and begin CPR.  VICTIM's un-inflated PFD was removed by emergency personnel while they performed CPR.  She was transported to the hospital in Jackson, where she was pronounced dead.  
  During the rescue efforts, a Teton County Sheriff's deputy and another rescuer inspected the PFD VICTIM had been wearing.  They later both told the investigating Wyoming Game and Fish Department game wardens that the PFD did not inflate and did not appear functional.  The PFD was not secured as evidence by deputies and GUIDE returned it to his boat when he left the scene after giving his statements to them.  Wyoming Game and Fish personnel were too far away to get the scene that day, so they interviewed PASSENGER 1 and GUIDE that evening and went to the scene with GUIDE the following day.  GUIDE retrieved the PFD worn by VICTIM from his storage unit and turned it over to the investigating game wardens.  At that time, the PFD was fully inflated.  GUIDE made statements indicating that he had turned the CO2 cartridge about half a turn before inflating it, indicating that it was possibly improperly armed when VICTIM was wearing it and would not have inflated if she tried to activate it.  The medical examiner who performed the autopsy ruled that VICTIM died from a myocardial infarction (heart attack) rather than drowning, as initially suspected.
  