Benazir Bhutto's chief security officer, who was with the former Prime Minister when she was assassinated, has been shot and killed in Karachi.

Khalid Shahenshah, 45, a longtime loyalist of the Pakistan Peoples Party (PPP), was killed on Tuesday when unidentified gunmen on motorcycles opened fire on his vehicle outside his home in the southern port city.

Ijaz Durrani, a spokesman for the PPP, said doctors were unable to save Mr Shahenshah, who was among a coterie of party security guards who failed to prevent the assassination of Ms Bhutto in a gun and bomb attack near Islamabad on December 27.

Police believe it was a targeted killing, and have opened an investigation.Khalid Mahmood, the Karachi police chief, said they did not yet know the motive but rumours about dark forces behind his murder are rife in Karachi.

Some government officials have indicated that the murder could be linked to Ms Bhutto's assassination. Mr Shahenshah was reportedly in the land-cruiser with Ms Bhutto when she was killed during an election rally in the garrison city of Rawalpindi. He stood next to her at her last rally on December 27 and has often been accused by some elements in the party of failing to prevent her assassination.

After he was caught on camera running his fingers over his neck in a gesture that mimicked slitting the throat, then pointedly looking at Ms Bhutto, suspicions grew that rather than simply failing to prevent her murder he was actively involved. The claim seemed to gain credence when Mr Shahenshah left the country for Dubai soon after Ms Bhutto's death.

A video of the Rawalpindi rally featuring his provocative gesture was played on Tuesday, by several Pakistani Television channels. However Rehman Malik, the federal home minister in a statement denied that he was under any suspicion.

The body guard was also allegedly linked with Pakistan's criminal underworld. The Dawn, Pakistan’s leading English newspaper, quoting police sources, claimed that he was a close associate of Dawood Ibrahim, a notorious Indian underworld don who was accused by Indian authorities of masterminding a series of bomb attacks in Mumbai in 1991 which killed hundreds of people. Mr. Ibrahim is believed to be living in Karachi. Police suspect the murder could be linked with rivalry with some other underworld group.

His assassination has eliminated a key witness to the former Prime Minister's murder.

Mr Shahenshah had also been involved in providing security for Ms Bhutto's widower, Asif Ali Zardari. Mr Zardari took over her party after her death and is the key power broker in Pakistan's current coalition government. Zulfikar Mirza, the home minister of Sindh province of which Karachi is the capital said the murder of Mr. Shahenshah was aimed at destabilizing the new government.

Mr Shahenshah was a prominent Karachi-based member of the PPP, whose loyalty began as a student activist. Aafter Ms Bhutto’s assassination, he became the chief security officer of party co-chairman Asif Zardari and was also in charge of Bilawal House’s security as well as being on duty during foreign tours.

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