At 0830 central time, a Beech A36 Bonanza was substantially damaged during a forced landing following a loss of engine power five miles north of the Lone Star Regional Airport. The pilot and one of two passengers aboard sustained serious injuries; the other passenger had minor inuuries. Shortly after takeoff, the engine started to misfire and sputter and the pilot turned back toward the airport. At an altitude of 2,000 feet, the engine quit. The FAA inspector who examined the wreckage repoerted that the fuel selector was observed in the right position. A small sample of fuel consistent with 100 low lead fuel was extracted from the left main fuel tank. A four-ounce fuel sample from the left wingtip tank was consistent with JET-A fuel.