Earlier in the prelims , Ledecky opened her first individual race of the Games with a new Olympic record of 3:58.71 to immediately lock the top seed for the final , clearing a four-minute barrier at the Games for the first time , and slashing 2.74 seconds off the mark set in London 2012 by reigning champion Camille Muffat of France , who was killed on a helicopter crash in March 2015
killed on a helicopter crash
2015 Villa Castelli mid-air collision
Swimming at the 2016 Summer Olympics – Women's 400 metre freestyle