GENEVA

A fire engulfed a public transport bus in the western Swiss town of Kerzers, Fribourg, killing six people after a person set themselves on fire aboard the vehicle, according to the initial investigation findings, police said Wednesday.

The Fribourg cantonal police said in a statement late Tuesday that emergency services were alerted at around 6.25 pm CET (1725GMT) to a fire on a postal bus on Murtenstrasse in Kerzers, in the canton of Fribourg.

The postal bus, known as PostBus, is a public transport bus service operated by Swiss Post that connects towns and rural communities across Switzerland.

When responders arrived, the vehicle was already fully engulfed in flames, according to the police statement.

In a statement on Wednesday, the cantonal police confirmed that the death toll stands at six. No further information is shared about the victims as the identification process continues.

Regarding the five injured, four passengers and a rescue worker, police said three of them were taken to hospitals while two were treated at the scene. Two of those hospitalized remained in the hospital on Wednesday, while one was discharged later Tuesday night, according to the statement.

According to the first findings of the investigation, the statement said, a person boarded the bus in the nearby town of Duedingen at around 5.45 pm CET (1645 GMT) and later set himself on fire in Kerzers at about 6.25 pm local time, causing the blaze to spread throughout the vehicle.

Police said initial hearings and witness testimony indicate that the incident was "a voluntary act without ideological motivation." The person is believed to have been a Swiss national living in the canton of Bern and may have been "psychologically unstable," who had previously been reported missing by family members. The suspect is also believed to have died in the fire.

The cantonal police said earlier that "a willful act could be the cause of the fire."

The investigation, led by the Fribourg Public Prosecutor’s Office, is underway to determine the exact circumstances of the tragedy, police noted.

The cantonal government expressed condolences on Wednesday to the families and relatives of the victims, describing the incident as a "tragic fire."

"It is a terrible tragedy that occurred yesterday in Kerzers," Stefan Regli, the CEO of PostBus and a member of the Swiss Post executive management, also said in a statement on Wednesday. "Like me, all PostBus and Swiss Post employees are shocked and deeply affected."