If president Trump gets one of his men in the Justice dept to fire special council Mueller, then he will be impeached.
IF he is innocent, he should let the investigation come to its end, which will prove his innocence.
They have speculated as to why Trump is so paranoid about people investigating him. Some think it's his former mafia financing ties, some think it's russian financing ties. Maybe he's afraid Mueller will subpoena his taxes, or his business records that would show him in violation of the emoluments clause for taking foreign money.
Just what is Trump afraid of?