Sir: Sindh has once again become a victim of security threats. Altaf Hussain’s arrest has posed serious security challenges. There has hardly been a dull moment since Chaudhry Nisar took over the charge of the ministry of the interior. So far he has displayed strong nerves and one would expect the same from him in the wake of any untoward incident in Karachi because of Altaf Hussain’s arrest. Hamza Gillani Lahore