Sectarian tension and Pakistan

Re: Sectarian tension and Pakistan

How and who do we round up when most of the time police and our intelligence agencies are unable to pin point the people behind the attacks?

We assume that it is because of sectarian tensions, extremists, revenge on Pakistan’s air strike, Al-Qaeda and many more. No one seems to know and every year blast happens, innocents get killed…speculations are made with some arrests but situation remains the same…why?