Hours earlier Hook, 52, had received a call from a fellow employee at the Los Alamos National Laboratory imploring him to head to the Santa Fe nightspot and hover by the bar. An excited, hushed voice had promised to corroborate Hook's explosive findings into massive financial irregularities at the birthplace of the nuclear bomb and proposed site for the Bush administration's new generation of atomic weapons.

Instead it is the brutal events that followed Hook's short walk that have plunged the top secret home of the U.S. weapons project into fresh controversy.

The attack was ferocious; a group of up to six men stomped on the head of Hook, a former internal auditor at Los Alamos, with such intensity that footprint marks were still visible on his swollen face days later. A witness claimed that without the intervention of the club's bouncer, Hook would have been murdered. His wife Susan later alleged that the assailants told her husband during the beating that "if you know what's good for you, you'll keep your mouth shut".

The attack last week came 48 hours before U.S. government investigators were scheduled to arrive at Hook's home and scrutinize audits detailing financial irregularities amounting to millions of taxpayer dollars at the New Mexico laboratory. Now he has been silenced.