ISLAMABAD - Mystery still shrouds the death of Kamran Faisal, an investigation officer of National Accountability Bureau (NAB), with police yet to make any breakthrough in the case despite questioning more than a dozen people in this regard.The special investigation team had questioned over two dozens people in connection with the case, but the interrogation failed to throw any lead, police said.Even after passage of three weeks after NAB investigation officer was found dead, it seems the police are still clueless, if it was a case of suicide or a murder.  A police officer investigating the case said on Monday that samples have been handed over to PFSA to ascertain cause of death.“We have provided the PFSA with all they had asked for. Now, we are waiting for the forensic laboratory report to further proceed,” investigation officer of Islamabad Capital police territory told TheNation on Monday. Contrary to what Islamabad police claimed on Monday that it has provided the PFSA with all thighs it sought in connection with Kamran Faisal case, a source from PFSA said police was yet to provide the information/material sought to determine cause of death.Pakistan Forensic Science Agency had asked the police investigation team to provide i) The ligature (knot) rope sealed in a clean paper bag. ii) The photographs of deceased in the hanging position, before the ligature was cut; iii) The photographs of the neck after the ligature was cut; iv) Photographs from all four sides (i.e. front, back, right and left sides) are required.“We are yet to receive the material,” a senior official of PFSA told TheNation on Monday.