A worker shot dead two colleagues then himself in the canteen of a Swiss factory.
Another seven people were wounded, six seriously, in the shooting at the Kronospan wood processing plant in the town of Menznau, Lucerne.
Police chief Daniel Bussmann said the 42-year-old gunman arrived at the premises shortly after 9am, drew a pistol and started firing at people.
Kronospan chief executive Mauro Capozzo said that the man had been “with us for more than 10 years a quiet man, no other incidents involving him are known.”
There was no word on a possible motive.
Gun ownership is widespread in Switzerland, thanks to liberal regulation and a long-standing tradition for men to keep their military rifles after completing compulsory military service.
But gun crime is relatively rare, with just 24 killings in 2009 or 0.3 per 100,000 inhabitants.
There have been several high-profile incidents over the years, including the killing of 14 people at a city council meeting in Zug, not far from Lucerne, in 2001.
Last month a 33-year-old man killed three women and wounded two men in a southern Swiss village.
