Just watched a BBC / PBS Panorma documentary 'Taliban Hunters' set in Karachi, from mid-December 2015, which reports (with my emphasis):
The Pakistani city of Karachi is one of the biggest in the world - and now one of the most dangerous. For more than two years, it has seen an onslaught of kidnappings, bombings and targeted assassinations by Taliban militants. The police are now fighting back, but they are understaffed, under-resourced and up against a deadly enemy. More than 160 police officers have been killed in the line of duty in just 12 months......286 Taliban prisoners in the city jail, 3 convicted; the criminal courts are scared to convict and the (new) anti-terrorism courts in action for a year have a 6% conviction rate.
Link, yes I know often not watchable in the USA:http://www.bbc.co.uk/iplayer/episode...aliban-hunters

Hopefully the PBS link does work:http://www.pbs.org/wgbh/frontline/film/taliban-hunters/

Rather oddly there is no mention of the para-military Rangers who have been deployed in the city, although I cannot recall how log for; nor the role of other agencies in CT.