Geneva is marking the tenth anniversary of the assassination of an Iranian opposition leader, Kassem Rajavi. The case caused an international political storm but has never been resolved.
A commemorative plaque, written by his friends, journalists and Geneva politicians, has been erected in the city.
The assassination of Rajavi in Coppet, close to Geneva, on April 24, 1990 continues to be a subject for discussion between Berne and Teheran. On a visit to Teheran earlier this year, aimed at cementing improved ties, a senior Swiss official urged the Iranian authorities to help resolve the case.
Rajavi was a senior figure in the main Iranian opposition group, the Mujaheddin, when he was ambushed and machine-gunned to death along the shores of lake Geneva.
The brother of the Mujaheddin's leader, Rajavi was well known in Geneva. He had been Iran's ambassador to the United Nations European headquarters in the city after the fall of the Shah and later turned against the Islamic regime, frequently denouncing abuses at the Human Rights Commission.
The government of Iran was soon accused of organising the killing. Within two weeks, pictures of suspected Iranian secret agents were published in the Swiss press. They were believed to have been part of a 13-strong team which organised the murder.
Two suspects were arrested in France in 1992 under an international warrant, and Switzerland put in an extradition request. However - in apparent reaction to diplomatic pressure from Teheran - the French government ignored Switzerland's request and allowed them to go back to Iran, citing "national interests".
Switzerland lodged a formal protest, but quickly moved to play down the diplomatic dispute. According to Swiss newspaper editorialists of the time, Switzerland had - despite its formal protests - avoided a potentially embarassing trial.
Sporadic attempts have been made to revive the issue. A sub-committee of the UN Human Rights Commission in 1994 called for the transfer of the two suspects to Switzerland to face trial. Three years later, 116 members of the Swiss House of Representatives called for the case to be re-opened. There has been neither an extradition nor a trial.
swissinfo with agencies