The Netherlands is taking legal steps in an effort to gain clarity about the cause of a fatal bus accident in Switzerland in 2012. The intention is to get a blood sample of the bus driver, who died in the crash, from the Swiss authorities, ANP reports

The accident happened in a tunnel in Sierre in March 2012. A total of 28 people were killed, including seven Dutch children. Many of the victims' relatives believe that the bus driver deliberately crashed the bus into the tunnel wall because medicine he was taking made him suicidal, according to the news wire.

The Netherlands already requested a blood sample in October last year. So far Switzerland refused.

"As the Swiss official investigation is completed, we are now trying through legal channels to get the blood sample", a spokesperson for the Ministry of Foreign Affairs said to ANP. "This is an ultimate attempt to answer the questions of relatives in the Netherlands. We hired a lawyer to examine the legal possibilities."

The spokesperson stressed that the Ministry currently has no reason to doubt the results of the Swiss investigation. The Ministry could not get the blood sample through diplomatic means, which is why legal steps are now being taken.