Australian police executed a search warrant August 5 on the offices of Exit International, the pro-euthanasia group led by Philip Nitschke, according to Australian Associated Press (AAP). Nitschke told AAP that homicide detectives were looking for information about the death of Inger Rijn in May.

Rijn and her husband Victor “were active members of Exit International, had attended meetings and collected information from the group,” AAP reported. While not confirming that the investigation involved Inger Rijn, a Victoria police spokeswoman told AAP that the search warrant concerned an alleged assisted suicide case.

Nitschke is a well-known proponent of assisted suicide, and his group has been the subject of several police investigations, according to The Age. Nitschke complained about the most recent search of the offices. “There have never been any charges laid. We are getting a bit fed up with this,” he told The Age. “This is not the first time the police have arrived at our [Melbourne] office out of the blue. The same happened in November 2009 over the suicide of another Exit member.”

Despite Nitschke’s objections, the police insisted the search followed protocol and was conducted with “sensitivity,” The Age reported. There has been no indication yet whether any charges will be filed.