The police on Friday registered a case against Sindh Home Minister Zulfiqar Mirza and Gadap Town Superintendent of Police Rao Anwar for their alleged involvement in the June 10 killings of Sindh Taraqi Pasand Party (STPP) workers. However, no arrests have been made as senior police officials have formed another inquiry committee to probe the case. The committee would investigate the home minister and several others, including police officials and STPP members.