A Swiss factory worker shot two colleagues dead and injured seven more today at a wood processing plant near the city of Lucerne, police said.
The shooting was already over and the killer was dead by the time police arrived at the scene.
Five of the injured are in a serious condition.
Lucerne police chief Daniel Bussmann told a news conference the 42-year-old attacker had worked at the factory in the town of Menznau, west of Lucerne, for ten years, but said the motive for the attack was not clear.
A prosecution spokesman said the shooting took place over two to three minutes, with the dead and injured found on the factory floor, in a corridor and the site canteen.
Police did not immediately confirm how the gunman had died.
Mauro Caprozzo, chief executive of the wood processing company Kronoswiss, denied rumours that job cuts were due to be announced at the factory today.
He said the killer was a quiet, unassuming character.
"One almost didn't see or notice him," Mr Caprozzo said.
Last month, a gunman killed three women and wounded two men in the Swiss village of Daillon.
That incident stirred a debate about Switzerland's fire arms laws that allow its male citizens to retain guns after their mandatory military service.
There is no national gun register but some estimates indicate that at least one in every three of Switzerland's 8m inhabitants keeps a gun, many stored at home.
Citizens outside the military can apply for a permit to purchase up to three weapons from the age of 18 in a country where sharp shooting and hunting are popular sports.
A shooting in the regional parliament of Zug in 2001 that caused 14 deaths prompted calls to tighten laws.
However, the majority of Swiss citizens rejected a proposal in 2011 for additional measures such as the creation of local arsenals for military weapons outside service periods.