The Federal Court has ordered the release of a Russian jailed for killing an air traffic controller he blamed for the death of his family in a plane collision.
Switzerland's highest court in Lausanne on Thursday rejected an appeal by prosecutors, who had opposed the reduction of Vitaly Kaloyev's sentence to five-and-a-quarter years from eight years.
Kaloyev was convicted in 2005 of premeditated homicide in the killing a year earlier of a Danish employee of the Swiss company, Skyguide.
The court ruling noted he had served more than two-thirds of his sentence with good behaviour.
The Danish controller was the only person on duty when a Bashkirian Airlines plane and a DHL cargo jet collided on July 1, 2002, in Skyguide airspace over Überlingen in southern Germany.
More than 70 people died in the crash, mostly schoolchildren on a holiday trip to Spain including Kaloyev's wife and two children.
The sentence against Kaloyev, whose case brought him widespread sympathy in his native Russia, was reduced by a regional Swiss court in July. It upheld his appeal that he acted with diminished responsibility because of the deaths of his family.
Zurich prosecutors appealed against the decision, which delayed Kaloyev's release that had been scheduled to take place on August 24.
Kaloyev has acknowledged that he must have killed the controller, but said he could not remember doing so.
In September, four Skyguide employees were found guilty of negligent homicide in a separate proceeding examining the events that led to the crash.
Three mid-level managers were given one-year suspended prison sentences, while another employee - a project manager - received a suspended fine of SFr13,500 ($11,200).
Handing down its verdict, the court in Bülach near Zurich said that the collision could have been avoided if two controllers had been on duty at the time.
swissinfo with agencies
Skyguide is a non-profit-making limited company that is 99% owned by the Swiss government.
It is responsible for air traffic control in Switzerland and parts of neighbouring countries.
Skyguide is based in Geneva, but a new Air Navigation Service Centre in Zurich is expected to be fully operational next year.