Updated

1992

1993 
Aleksei Tikhomirov and Oleg Baranov were sentenced to three-and-one-half years in prison after stealing 4.5 kg of low-grade uranium from Russia's Sevmorput naval shipyard. The arrest was made after Tikhomirov's younger brother asked a fellow officer at the naval base to help sell the stolen material.

1994
During a German police raid on the house of Adolf Jaekle, a businessman under investigation for counterfeiting, 6.15 grams of nearly pure plutonium were discovered. The material was believed to have been smuggled from a research laboratory in the former Soviet Union or Eastern Europe. Jaekle was found guilty and sentenced to five-and-one-half years in prison.

1994 
Germans Gustav Illich and Vaclav Havlik were arrested for selling stolen nuclear materials to an undercover agent. Only a small amount of their 800 mg of highly enriched uranium was recovered, making this the first case with hard evidence that more bomb-grade material was hidden somewhere.

1994 
German Justiniano Torres Benitez and Spaniards Julio Oroz and Javier Bengoechea Arratibel were arrested on Aug. 10 at the Munich airport after carrying 560 grams of mixed-oxide reactor fuel from Moscow. The fuel contained 363 grams of weapons-grade plutonium.

1994 
On Dec. 14 Russian trader Alexander Scherbinin, Prague physicist Dr. Vagner and Belorussian Kunicky were arrested for possession of 2.7 kg of weapon-grade uranium. The nuclear material was identical to the uranium that Germans Gustav Illich and Vaclav Havlik were arrested for earlier in the year.

1995 
The Russian Security Service arranged an undercover buying operation in June to obtain 2 kg of low-grade uranium. Before the arrest was made, however, a local police car arrived and men opened fire with an automatic weapon, spraying the agents and traders with bullets.

Source: Frontline — www.pbs.org/wgbh/pages/frontline/shows/nukes/