A British nuclear energy expert who plunged 40 metres to his death at the United Nations' (UN) building in Vienna may have been murdered, police said today (Thurs).

Timothy Hampton died on the spot on Tuesday after falling from a 17th floor window at the Vienna International Centre (VIC) - one of the UN's three headquarters.

The UN confirmed the death of the 47-year-old – who was involved in disarmament negotiations with Iran as a member of the UN's Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) – but refused to give any further information on the circumstances of the fatality.