The flight was in level cruise and 3 of the 4 jumpers were positioned on the step ready to jump. The reserve chute on one of the jumpers accidentally deployed and was sucked forward and over the right wing leading edge. The jumper was pulled forward and over the wing, and in the process, hit his head on the wing leading edge and substantially damaged the internal wing structure. As the jumper's chute deployed over the wing, the aircraft was rolled inverted. The other jumpers jumped and parachuted to the ground safely. The pilot regained control of the aircraft. The parachutist whose reserve chute deployed was found fatally injured. The parachute involved in the accident was examined by a master parachute rigger under the supervision of FAA airworthiness inspectors. According to the rigger's report, the automatic opening device for the reserve parachute was found activated, however, no determination could be made about when the device triggered. No other anomaly in the parachute system was found.