ST. PETERSBURG, Fla.—A rising middle school football player in Missouri, only 14 but already 6 feet, 5 inches tall and well over 300 pounds, Tyre Sampson fell to his death from a towering Florida amusement ride. Lawyers for his family want to know if negligence about his size, or other factors, played a role. “This young man, he was athletic and he was big. He had no way of knowing,” said Bob Hilliard, a Texas attorney who represents Tyre’s mother, Nekia Dodd, in an interview Saturday. “This is going to be an issue of a lack of supervision and lack of training. A straight-up negligence case.” Investigators on Saturday continued to examine what happened Thursday night when Sampson dropped out of his seat from a 430-foot, free-fall amusement park ride that is taller than the Statue of Liberty along a busy street in the heart of Orlando’s tourist district not …