The former Pakistan Army chief under investigation for his alleged role in facilitating nuclear exports first attracted worldwide attention 16 years ago following the air crash that killed the nation's then president, Zia ul-Haq.

Intelligence experts are questioning General Mirza Aslam Baig, the father of the Pakistani nuclear bomb Dr Abdul Qadeer Khan and a host of other scientists over their role in selling nuclear weapons technology to Libya, North Korea and Iran.

But Gen Baig, Pakistani opposition sources in London have told rediff.com, merits attention for another equally important reason.

He was the senior army officer who elected to travel on an escort plane rather than on the president's C-130 aircraft that crashed a few minutes after taking off from Bahawalpur.

Zia, US ambassador to Pakistan Arnold Raphael, the head of the US defence mission in Pakistan, General Wassom, and 27 others were killed in the crash.

A subsequent report blamed sabotage, but to date it is not known who was responsible.

US forensic scientists pinpointed the presence of a secondary high explosive, pentaerythritol tetranitrate in the plane.

Antimony was found in the mangoes that were given as a last-minute gift to the president.

The presence of these chemicals, which the report indicated could have been triggered by a remote device, could have incapacitated the pilots.

As the plane began to lurch violently after take off, Najib Ahmed, Gen Zia's military secretary, was recorded as shouting to the pilot (Captain Mashoud), 'Mash'houd! Mash'houd!'

Minutes later the plane crashed.