The gunman walked into the staff canteen at the Kronoswiss wood-processing factory at Menznau, near Lucerne, Switzerland during a staff breakfast break and began shooting.
Police said the 42-year-old suspect, who was not named, had worked at the plant for a decade and did not fire at random but picked off specific colleagues with a handgun.
A spokesperson for Kronoswiss, which employs about 450 workers, said the gunman had always been “very calm” and “somebody you would not notice” during the time he worked for the company.
It wasn’t immediately clear how the gunman died. Gun ownership is widespread in Switzerland due to a long-standing tradition of allowing those who complete their compulsory military service to keep their rifles and weapons.
Many serving in the military are reservists allowed to store weapons at home. A referendum in 2012 aimed at tightening firearm controls was defeated.
The number of gun crime is low with 24 killings in 2009, a rate far lower per capita than in the US.