How are Sagar-Runi killers evading justice?

On February 11, 2012 Sagar Sarwar and Meherun Runi, two very promising journalists, were brutally murdered in their apartment, leaving their son Megh behind. The incident was so macabre that the whole country was numb with shock and disbelief. Since then two years have passed, but the murderers are still at large as the law-enforcing agents could not make any headway about the killing. This is unacceptable because they are capable and we have seen many times how swiftly they have arrested criminals guilty of different crimes.
But why are they failing in the Sagar-Runi case? Is   the case destined to never give up its mystery? What could be the reason behind it? The journalist community must not give up its quest for the truth to be revealed, and the common people are with them in their struggle to bring the killers to justice. They must not rest until the goal is achieved.
Nur Jahan
Chittagong