Well when Achut Krashana was sacked by the commie govt. Dhurba Bdr. Pradhan(then IGP)  and Bam Dev Gautam (then a home minister) used to smuggle gold from HK. I was told from a very reliable source that once all passengers from RA flight from HK had left the plane, a police van was used to transfer all gold from the flight to some undisclosed location. Probably this gold was used to buy weapons for the Maoists. AND that could be the link.