Dutch police conducted a search of the office of suicide pod inventor Philip Nitschke in Haarlem on Monday on behalf of the Swiss authorities, the public prosecution office has confirmed.

Police confiscated computers and a prototype of the Sarco suicide pod, a later version of which was used last week to end the life of a 64-year-old American woman in Switzerland.

Assisted suicide is allowed in Switzerland under certain conditions. However, the Swiss public prosecutor is now questioning if the use of the pod, which fills up with nitrogen gas when the person inside pushes a button after declaring he or she wishes to die, constitutes incitement and aiding and abetting of suicide which is illegal. It is also investigating if other offences have been committed.

According to Swiss monitoring body Swissmedic the pod does not qualify as a “therapeutic” medical instrument because its aim is to kill and not to cure.

Several people involved in the incident, have already been detained.

Nitschke, an Australian national living in the Netherlands and a long-time right-to-die campaigner, was not present at the suicide but followed it via a video link. “It looked exactly as we had expected. I estimated that she lost consciousness within two minutes and died after five minutes. We saw some twitchy movements of the muscles but she was likely already unconscious,” he told the Volkskrant.

It is not yet known if Switzerland will ask for the extradition of Nitschke and his wife Fiona Stewart who is a lawyer and board member of the Last Resort, the organisation which offers the use of the suicide pod.

Nitschke and Stewart said they were shocked by the reaction of the Swiss justice department but were confident they would not be prosecuted, their lawyer Tim Vis told the paper. “They have always made sure their actions are within the law, and they did so in this case,” he said.