The airplane was substantially damaged when it crashed into Old Tampa Bay at about 1538 Eastern time. Visual conditions prevailed. The private pilot and two passengers were fatally injured. A witness reported seeing the airplane flying at an estimated altitude of 100 feet, then saw the airplane in an estimated 90-degree right bank. The airplane then rolled into a 45-degree left bank, followed by rolling wings-level. The airplane was then observed in a 10-15 degree nose-up attitude. The airplane then stalled and descended in a nose- and left-wing-low attitude.