You are being used as money mule. You receive dirty money and provide clean money for a good profit.
If you get caught, ignorance is not an excuse and you may get jailed for doing this.
10% profit should be enough to know that there is something fishy about this deal.
^^This. Don't do it, OP. Someone's using you to launder. And guess who the authorities will catch first? It ain't worth 10%. You're right to ask questions.