Shahram Amiri, the Iranian scientist who took refuge in the Pakistani embassy in the United States today, is a nuclear physicist in his early 30s.
Amiri was a researcher at Malek Ashtar university of defence technology, which was listed for sanctions by the European Union in 2008. The university, according to the EU, was linked to Iran's ministry of defence and "set up a missiles training course in 2003".
The rector of the university, a lieutenant general, was named in the UN security council's first round of sanctions on Iran in 2006 as one of seven "persons involved in the nuclear programme".
Iranian media refer to Amiri as an academic. The head of Atomic Energy Organisation of Iran, Ali Akbar Salehi, has denied any links with Amiri. Amiri has never been employed by the agency.
In October, Amiri's wife told the hardline Iranian newspaper, Javan (Youth), that her husband was "only a researcher and did not hold any government post".
The unnamed woman added: "His research was in the field of physics as it was his specialised subject. Since he reached Saudi Arabia, the Saudi government must be held responsible for his disappearance. It has been four months that we have had no news from him. The last time he called was from Medina. He had gone there on a pilgrimage visa."
Three months after Amiri's disappearance during the June 2009 pilgrimage to Saudi Arabia, Iran admitted to the UN's nuclear watchdog that it was building a small uranium enrichment plant near Qom, south of Tehran - a day before Barack Obama announced its existence to the world. There have been suggestions that Amiri worked at the Qom facility.