The bomber rammed his explosives-laden vehicle into Aslam's motorcade at Hassan Square in Gulshan-e-Iqbal area of Karachi as the officer was returning from a successful operation that resulted in the killing of three suspected militants.
Four policemen were injured in the attack. The powerful blast, which was heard from several kilometres away, blew out windows of many buildings in the area.
The Mohmand chapter of the banned Tehrik-e-Taliban Pakistan claimed responsibility for the assassination.
Footage on television showed the mangled remains of Aslam's car and a huge cloud of smoke rising over the area.
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Aslam, who led several drives against criminal gangs and the Taliban in Karachi, had escaped several attacks in recent years. In 2011, Aslam escaped unhurt when his home in Karachi was targeted by terrorists though eight others were killed by the blast.
The official had joined the CID as head of its Counter-Terrorism Unit in 2009. He later became chief of the Anti-Extremism Cell in 2010.