Karachi's Complex Culture of Violence - by Madiha Sattar The AfPak Channel
A backgrounder on why Karachi has had a continous indigenous propensity for violence since the 1980's, which flares up depending on the situation.
Madiha Sattar also mentions how there has been a pattern of violence since 2009 and at a slightly lower rate throughout 2010, bringing it up for the international community to know.
And here's the main thing about Karachi:
The police and the paramilitary rangers are famously limited to main roads in many of the city's neighborhoods, whose inner streets are controlled by arms-bearing gang members operating beyond the reach of the law.
I must state, having known citizens from Karachi, that this constant state of lawlessness exists for every Karachi-ite and has existed for them since the 1980's.