International attention is now focused on the two daughters of Dr A Q Khan following speculation that one of them was used as a courier to smuggle incriminating documents out of Pakistan.
Both daughters were hurried out of Amsterdam in 1976 after Khan left Holland with stolen blueprints and technology subsequently used to generate the enriched uranium that Pakistan required to manufacture its nuclear weapons.
Khan became a national hero in Pakistan following the 1998 nuclear tests, but in recent weeks he has been under a cloud following his admission that he traded his stolen expertise for cash and other perquisites from North Korea, Libya and Iran.
He was pardoned by President Pervez Musharraf last week after publicly apologising for his role in the illegal dissemination of nuclear weapons know-how, but it has since been disclosed that he still holds a trump card in the shape of documents that incriminate both Musharraf and other senior army officers in Pakistan's clandestine nuclear trading.
It is these documents that are believed to have been smuggled out of the country by Dina, Khan's older daughter, who was educated at the University of Sussex in Brighton.
Twice divorced Dina, who is entitled to a British passport because of her mother, is also thought to hold the key to some of Khan's extremely lucrative real estate investments in the UK that were funded by his nuclear sales.
London's Sunday Telegraph newspaper cites Pakistani intelligence officials as saying that Khan had agreed to surrender the documents in return for a blanket pardon, but failed to do so.
The newspaper quotes the unnamed intelligence official as saying, "The government has been trying to retrieve the documents since Dr Khan was offered a presidential pardon last week but they are yet to receive them, even though he promised."
Dina has homes in Holland, Dubai and London, so her precise whereabouts will remain a mystery for the time being. She will also try to keep a low profile, out of sight from Pakistani diplomats who may want to question her.
Her younger sister, Ayesha, is back in Islamabad and staying with her parents after her divorce. She too lived in London until 2000 where her husband was First Secretary (commercial) at the Pakistan High Commission.
More from rediff