It's a well-known fact and have been told several times in the past.
However a large number of MQM leaders were involved in that activity.
Yet it is a fact that MQM memcers often had no choice but to act on the orders of Altaaf and his close mafia. Similarly Karachi businessmen/bankers had to obey him as well.
What will be gained by this investigation ?- Let's catch the real culprits who really benefited with money laundering by some other investigation. better to give some space to MQM leaders who wish to reform and have fully disengaged from Altaaf.