Can next of kin claim compensation for state negligence?

Dear Sir, my father and brother in law were murdered in a case of suspected robbery gone wrong in a case dating back to 08.08.2008. The case went to trial in 2017 and since then nothing has been heard from the court. My father and brother in law was returning home and, on their way back, stopped at an eatery and there a criminal looted the ornaments and killed them without any provocation or fault of the deceased. My question is that when the state has the responsibility to maintain law and order and to protect the life of the citizen and due to the state's failure, my father and brother in law lost their lives so can the next of kin are eligible to demand compensation for the failure of the state's constitutional duty and under which law.