Police in the Pakistani capital today lodged a First Information Report over the mysterious death of an anti-graft investigator who was probing corruption charges against Prime Minister Raja Pervez Ashraf and other top political leaders.

The FIR regarding the death of National Accountability Bureau officer Kamran Faisal was registered at the Secretariat Police Station at the request of NAB Assistant Director Noman Aslam, police officials said.

Aslam requested that a murder case should be lodged against unidentified persons as there were rumours that Faisal has not committed suicide.

He asked police to launch an investigation to find any culprits involved in the case.

The FIR was registered under Section 302 of the Pakistan Penal Code, which relates to murder.

Faisal was found hanging from a fan in his room at a government hostel a week ago.

He was probing allegations that Prime Minister Ashraf and other senior political figures had accepted bribes to allow the setting up of "rental power projects".

Though an interim autopsy report concluded Faisal had apparently committed suicide, his family and colleagues disputed the findings and demanded an independent probe.

The government has set up a judicial commission headed by a retired judge to investigate Faisal's death and the Supreme Court has launched a parallel probe into the matter.

At a hearing yesterday, a bench of the apex court had pulled up NAB officials for failing to register an FIR on Faisal's death.