Same thing happened in sikkim. India helped influx of people of nepalese root to sikkim first, bargained with Chogyal to allow nepalese people take part in politics. In 1973, first, 8th Gorkha regiment raided at Chogyal's palace and deposed him and later India help conduct a "militarized" referendum when  sikkimese leaders of nepalese descent became instrumental in annexation of Sikkim to India. Nepal is going through same route but without any military intervention. Our PRAJATANTRIK, GANATANTRIK and AGRAGAMANKARI leaders are helping this.
Yesto sthiti dekhera hami ke nai po garna sakchhau ra? Tulutulu heryo basyo.
P.S. Annexation of Sikkim was the first "big" job of RAW.