<p>KARACHI, Pakistan -- The scientist behind a worldwide black market in nuclear technology is involved in high-stakes brinksmanship over his future, refusing to hand over reportedly incriminating documents demanded by Pakistani authorities.</p>
<p>The documents and a tape-recorded statement, which are said to demonstrate that senior Pakistani army officials -- including President Pervez Musharraf -- were aware of Abdul Qadeer Khan's nuclear proliferation activities, are believed to have been smuggled out of the country for safekeeping by the scientist's daughter Dina.</p>