On April 24, 1830, Govindchandra was murdered in his Capital¹⁵. On the previous night a gang of Manipuris in concert with some attendants entered the royal apartment and killed the Raja and several members of his family and set fire to the palace. On receiving the news Mr. Furgund, the Magistrate of Sylhet, hurriedly posted a detachment to Cachar and reported the matter to the Government of Bengal. The Government appointed Lieutenant Fisher, who was by then on survey duties at Sylhet to take temporary charge of the administration in Cachar with the powers of a magistrate and collector¹⁶.

It was strongly suspected that Gambhir Singh instigated the murder of the Raja of Cachar. It was also believed that Tularam had a secret hand in the murder of the Raja¹⁷. Ram Govind, acting vakeel on the part of the British Government at the Court of Raja Govindchandra was suspected to be privy to the whole plot¹⁸. Kirparam Brahman Cachar in his deposition¹⁹ stated that he had seen about thirty Manipuris with ‘muskets and sword’ which belonged to the late Raja of Cachar and the ‘Golden necklace’ of the late Raja on the neck of the one of the Sirdars. He further pointed out that one Suntaba, blind in one eye, a subject of Gambhir singh had in retaliation for some previous offence, killed Govindchandra with a sword²⁰. The depositions of the persons who were connected with the crime established reasonably that Gambhir Singh sent his agent to Cachar to kill Govindchandra²¹. Evidence proved that a party of armed men from without, assisted undoubtedly by some of the Siphahis on the Raja’s own service, penetrated the interior of his dwelling and murdered him there. Lieutenant Fisher, after making a through and detailed study of the case, opined that the assistance of domestic conspiracy was more certain than was at first supposed and that the Raja was murdered through the machination of Gambhir Singh. Though there were considerable number of Cacharis holding situation in the Raja’s family about the time of his murder, there was no direct proof of their participation in the crime²². Fisher further reported that though the murder was committed by the followers of Gambhir Singh and probably by his orders, yet several principal Cacharis in the Raja’s family were also more or less implicated. It was even possible that the conspiracy might have been parched among the junior officers without the direct concurrence of Gambhir Singh²³. However, a close examination of the evidence indicated the complicity of Gambhir Singh.

The Government of Bengal wrote that the presumptive proof against Gambhir Singh as the instigator of the murder was very strong²⁴. While doing so the Government also considered the repeated disputes between the two chiefs over several matters and only about a fortnight before the occurrence, Govindchandra had to solicit the Agent to the Governor-General for military aid against Gambhir Singh, who was reported to have despatched a force to seize Cachar in concert with Tularam. The Agent, therefore, asked Gambhir Singh to tender his explanations for the charge made against him in connection with the murder of Govindchandra and to surrender Heeranund, Suntaba and such others who were suspected to be involved in the crime²⁵. However, the Government of Bengal did not approve of the suggestion to arrest Gambhir Singh in the event of his visit in Sylhet²⁶.

Several claimants appeared to the vacant throne of Cachar. Gambhir Singh requested the Government of Bengal to allow him to hold the country of Cachar for twenty years in return for an annual revenue of Rs. 15,000²⁷. Captain Grant supported Gambhir Singh’s claim. He was under the impression that the acquisition of Cachar by the latter would provide him with sufficient means to build up a stable and efficient Government so necessary for the security of the North Eastern Frontier. If Cachar be ceded to the Raja of Manipur, Grant also believed that there were ample chances for assimilation of the two peoples in Cachar and Manipur who had been warring all along with each other²⁸. Cachar being separated from Manipur by a series of ranges of hills and deep rives and its inhabitants speaking a dialect quite different from the language of the Manipuris, Captains Jenkins and Pemberton did not support Grant’s argument. They, therefore, opposed Gambhir Singh’s claim on Cachar. The Government of Bengal concurred with the arguments of Jenkins and Pemberton. Moreover, on the receipt of the proceedings of the murder of the late Raja, the Supreme Government felt it impolitic to permit Gambhir Singh to profit by a crime which was suspected to have committed at his instigation and deemed it inexpedient to transfer the country of Cachar to the Raja of Manipur. Accordingly Cachar was annexed on August 14, 1832.