PATIALA, India: The Patiala police have not been able to make any breakthrough in the investigation of the murder of Dr. Manjit Singh Mangat who was shot dead ‘a few days back. The police have yet to ascertain the actual number of assailants. There were two assailants on the motor cycle who fired’ two bullets each according to one version. The second version is said that there were four assailants on two motor Cycles. The police have not been able to ascertain the killer’s identity from the accounts given by two eyewitnesses who gave details of the incident to the police. Meanwhile various militant groups claimed the responsibility for the crime, but it is not sure which group really was responsible. The police sources say that search parties sent to various parts of the state have not met with any success.