You don't know how transferring your development offshore to a group that reports to an outside investor can kill a company?

Just asking for clarification here... Honestly sounds like a What The (Cluster) Fuck in the making...

It's not about the stake or the developers. The whole deal sounds fishy. Why won't the investor provide references? Why should the decision be made right away (next day or two)? Why shouldn't this person publicize the site?

When it looks too good (or too suspicious) to be true, it probably is.

10% of the company owned by a random con man would be a big red flag to any real investors in future funding rounds.