A Swiss community is in shock after a factory worker opened fire on colleagues, leaving three people dead and several others injured.
The shooting was already over and the killer was dead by the time police arrived at wood processing plant near the city of Lucerne.
Five of the injured were 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 10 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.
Mauro Caprozzo, chief executive of the wood processing company Kronoswiss, denied rumours that job cuts were due to be announced at the factory.
He said the killer was a quiet, unassuming character.
"One almost didn't see or notice him," Caprozzo said.
A gunman killed three women and injured two men last month in the Swiss village of Daillon, stirring a debate about Switzerland's firearm laws that allow men to keep guns after their mandatory military service.
There is no national gun register in Switzerland but some estimates indicate that at least one in every three of the country's eight million 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 Zug regional parliament in 2001, in which 14 people were killed, prompted calls to tighten the law, but the majority of Swiss citizens rejected a proposal in 2011 for extra measures such as lock-ups for guns outside service periods.