NEW DELHI: The Indian Navy has started general court martial procedure against three senior Navy officials after they were found guilty of dereliction of duties by a high-level inquiry into an accident involving frontline warship INS Betwa in 2016.Official sources said the court martial procedures against two commanders and a captain began in Mumbai on July 26 after they contested the findings of the board of inquiry which probed the "rare accident".Two sailors were killed when the Brahmaputra-class guided missile frigate capsized during undocking at the Naval Dockyard in Mumbai on December 5, 2016.The then captain of INS Betwa is among the three officials facing the general court martial.