Very interesting yet heavy weighted topic you brought here. Nepal should have never let Maoists come to power. There should have been no negotiations with them terrorists. How come murderers do any good to the country and its people?  If they finally had to come to politics and be no different than NC, UML, why did they start war in the first place? 
We, Nepalese people are very innocent (sojho) by nature. We easily trusted the Maoists. Maobaadi le kehi garchha ki vanera we voted for them because at that time, none of the political parties were doing anything for the betterment of the country. 
Maoists could be punished at that time when they first came to power. We could have protested and not accepted terrorists to be our representatives. We could have demanded to take them to international court, and our voices might have been heard. But, we supported them thinking, at least we get peace by ending civil war. I think Nepalese people didn't support Maoist, but took it as a trade-off for peace in the country. Now, it will be very hard to make them accountable because it looks like we supported them back in the day. But could be possible. 
I think the easy solution is to denounce the Maoist party as we all know they are mere killers, with no soul. People should not give importance to them; media should not go to the press conference organized by them; don't broadcast anything about them. Make them so unpopular they go away. If they don't go away, then we need some brave souls who can put bullets into some of them's head; we all know the deserving candidates. I have a very strong feeling that somebody from their own group will end the so called leaders out of frustrations.