The 42-year-old machine worker who killed three co-workers at a Menznau wood plant in central Switzerland last month died from a bullet to the head fired from his own pistol, Lucerne cantonal police investigators say.

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The bullet was either fired intentionally by the gunman in an act of suicide or the gun went off by accident during a scuffle with another employee at the Kronospan plant, police said at a press conference in Lucerne on Thursday that shed new light on the deadly February 27th shooting spree.

The shooter, a Swiss citizen originally from Kosovo identified as Viktor B., was almost certainly not killed by another person, said criminal police chief Daniel Bussman, the ATS news agency reported.

Family relatives of the shooter earlier said they did not believe he committed suicide.

This conclusion was reached by investigators after they interviewed witnesses of the incident, viewed surveillance videos and received an analysis from the local forensic institute.

Following an initial investigation, police said the killer was carrying two fully loaded handguns, a revolver and a pistol, along with ammunition in a bag, Bussman said.

The gunman fired 18 shots, wounding six employees in addition to the two male and one female co-workers he killed.

Those who died included a canteen worker and a wrestling champion.

Five of the wounded victims were seriously injured with two of them still receiving treatment in hospital.

In recapping what happened, police said the machine worker walked down a corridor and shot three people in an office before heading to a cafeteria where he continued shooting, ATS said.

Seventeen people dived under tables but a man in the cafeteria seized a chair and attempted to stop the man from shooting.

The police description of what happened confirmed earlier reports of employees’ courageous acts to prevent the gunman from killing or wounding more people, ATS reported.

Viktor B. fired at the man who received a bullet in the jaw but was still able to grab the killer, police said.

In the ensuing scuffle the two men fell to the floor.

The gunman did not move and another employee struck him on the back with another chair.

According to witnesses the shooter still had a pistol in his hand after the fatal shot was fired.

They testified that an employee took the gun out of the man’s hand and threw it out a window.

Police said the exact reasons for the gunman’s actions remain unknown, according to the ATS report.

Born in Kosovo, he obtained political asylum in Switzerland in 1991 and became a Swiss citizen 10 years later.

Police added that the pistol used by the gunman was acquired illegally while the other handgun, which he did not use, was bought legally, although he did not have a permit to carry either weapon.