GENEVA, Dec 28: A Swiss man suspected of involvement in the world’s biggest nuclear smuggling ring has been released from prison after more than four years of investigative detention, his family said on Sunday.

Urs Tinner, 43, was freed several days ago, his mother Hedwig Tinner told The Associated Press by telephone from eastern Switzerland.

His brother Marco Tinner, 40, remains in detention while prosecutors appeal his release to the federal criminal court in Bellinzona, she said.

The Tinner brothers, along with their father Friedrich, are suspected of supplying the clandestine network of Abdul Qadeer Khan with technical know-how and equipment that was used to make gas centrifuges.

A public trial for the Tinners could prove uncomfortable to the Swiss government. According to court documents, federal prosecutors believe the Tinner brothers were CIA informants and that US pressure prompted the Swiss government to destroy some of the evidence in the case.—AP