Laramie, WY – Murder-suicide is how investigators classify the 2005 deaths of an Arizona man and his teenage son, at Yellowstone National Park. Investigators for the National Park Service believe 50-year-old Drew Speedie of Scottsdale, Arizona, pushed his son, Brent, off a bridge and then jumped to his death. The bridge is 200 feet above the Gardner River. Investigators say they'll never know for sure what happened. The murder-suicide conclusion is based on several things, including physical evidence, the position of the bodies and information that Drew Speedie had talked about suicide. Speedie, his wife, Irene, and 13-year-old Brent were on the last day of a Yellowstone vacation in September of 2005 when the father and son went to the Gardner Bridge. Irene stayed at a hotel. The bodies of Speedie and the boy were found hours later, at the bottom of a canyon.