In 2374, Rekar led a successful hijacking of the Federation starship USS Prometheus, killing the Federation crew. He and his officers were the first to prove the effectiveness of the experimental multi-vector assault mode in combat conditions by disabling a pursuing Nebula-class starship.
Rekar and the others were eventually rendered unconscious by neurozine gas, introduced into the life support systems by The Doctor, working together with the Prometheus' EMH Mark II. The vessel was then returned to Starfleet control. (VOY: "Message in a Bottle")