Who would trust our FBI to question anyone. Didn't they shoot Tsarnov's friend six times when they questioned him in his own living room?
All the more reason to let the FBI to do the questioning —
Furthermore it’s clear that the Malaysians aren’t going to even though they have a lot of wood and water over there.
There they have the cousin of the main suspect daring them to “go there” and even mocking them and they are still afraid to bring him in for questioning.