I will give you a hint: look in your iventory and read the message you found about the Shiri-Ryu that says they pose as Raidens followers... then look for some of his followers in Earthrealm

I did that. The letter said that the followers were disguising themselves as followers of Raiden. I walked up to the villagers and knocked them all out, but to no avail.
What to do?

I talked to the woman (in the center hut) she rambled on and then you have to fight scorp (and you are sub zero). you win that fight and get some proof to take back to the base

Thanks a bunch!