A 61-year-old German engineer became the latest European scientist arrested on suspicion of helping Libya's now abandoned effort to build a nuclear bomb, German prosecutors said Tuesday.

  Swiss authorities arrested the engineer, identified only as Gotthard L., on Nov. 13 in the canton of St. Gallen, acting on an international warrant, according to the German federal prosecutor's office.

The name of a German living in Switzerland, Gotthard Lerch, has previously emerged in investigations by the International Atomic Energy Agency, the U.N. nuclear watchdog agency.

The engineer was arrested on suspicion that he helped in the development of a gas centrifuge to enrich uranium for use in atomic weapons, for a fee of up to $4.25 million, said Frauke Scheuten, a spokeswoman for the German prosecutor's office.

The arrest came during an investigation into the nuclear proliferation network of Abdul Qadeer Khan, the Pakistani nuclear scientist who admitted in February that he passed nuclear technology to other countries, and was the latest involving a European, according to prosecutors.

In August, German authorities arrested Gerhard Wisser, whom they described as a main suspect. He was released on bail but re-arrested in South Africa in September. Gotthard L.'s home was searched at the time, but authorities lacked evidence to arrest him, prosecutors said. Last month, they arrested Swiss engineer Urs Tinner, 39, on allegations he was a member of the ring.

The three are accused of attempting to deliver centrifuge parts made by a South African company to Libya between 2001 and 2003 at the request of Buhary Seyed Abu Tahir, a Sri Lankan who prosecutors said was a middleman between the network and Libya.

The parts were shipped to Dubai and loaded onto a German-registered freighter with false customs papers, headed for Libya, but are not believed to have reached their destination, prosecutors said.

The IAEA said in January that Pakistani scientists were involved in selling technology to Iran, Libya and North Korea. The Pakistani government detained several scientists, including Khan, the father of Pakistan's atomic bomb and a national hero. He admitted to the charges but was pardoned by President Gen. Pervez Musharraf.

The agency's announcement came a month after Libyan leader Moammar Gadhafi renounced his weapons programs — a move meant to help rebuild relations with the West. The European Union last month ended 12 years of sanctions against Libya and eased an arms embargo, and the United States lifted most of its commercial sanctions in April.