After the blast on 10 January 2013 in Quetta, protests were started all over the Pakistan, Protesters not only blocked the all national highways of Pakistan but the trains and airports as well. Protest was recorded at 25 places in Karachi, including before the Bilawal house. President Zardari was inside the Bilawal house so due to the critical situation and security measures Govt. not only jammed the mobile networks but called the police and water canons etc.
At the same time Sharjeel Memon and Pir Mazhar ul Haq were sent to the protesters from Bilawal house to end this protest after the discussion, but the demands of protesters were based on the demands of protesters of Quetta. When Sharjeel Memon and Pir Mazhar ul Haq arrived to discuss some young guys attacked both and beat them up. Here is the video check it.