The Federal Court of Justice in Bellinzona found the Swiss Friedrich Tinner, 75, and his two sons - Urs, 46, and Marco, 43 - guilty of supplying technology and expertise to Muammar Gadhafi's nuclear weapons program until 2003. Only then, and under international pressure, did Libya give up its atomic pursuits.
The court on Tuesday handed the elder Friedrich a two-year suspended sentence; Urs got 50 months, and Marco 41. They have to pay fines and legal costs, but were free to leave the courtroom because they had served time in custody. The sons were arrested in 2004 and 2005.
The US had lobbied Switzerland not to indict the Tinners and to destroy sensitive evidence. A US probe had helped bring an end to the international smuggling network of the Pakistani engineer Abdul Qadeer Khan, the so-called father of the Pakistani atom bomb.
Case dates back to 1990s
The case began in the 1990s, when the Tinners started working with Khan's network to supply Libya.
Khan remains under house arrest in Pakistan and has escaped prosecution. Other engineers in the so-called Khan network operated in Turkey,
Britain, Spain, Dubai and South Africa.
The Tinner trio had refused to shed light on their cooperation with the CIA as the hearing began on Monday.
When asked why he had not informed Swiss authorities of his informant work, the father said the matter had been "in good hands" with his US counterparts.
The court did find the Tinners guilty, however, of supplying equipment and know-how and manufacturing centrifuges in Malaysia, resulting in the fines.
Mark Fitzpatrick, a nuclear policy expert at the International Institute for Strategic Studies in London, who has been following the case, told the German news agency dpa that the "Tinners were absolutely central to the Khan network."
mkg/ipj (AFP, AP, dpa)