Advocacy organizations behind a controversial “suicide capsule” have paused their application process amid an ongoing criminal investigation in Switzerland.

Last month, the group reported receiving more than 370 applications to use the device. Yet a co-president, Florian Willet, of a Switzerland-based organization, the Last Resort, remains in pretrial detention, according to statements from the group and Exit International, an affiliated organization originating from Australia more than 25 years ago.

The investigation follows the death of a 64-year-old woman from the U.S. She became the first individual to employ the device, known as the “Sarco,” on September 23. The incident occurred in a forested area in the northern Schaffhausen region, near the German border. Swiss authorities have also detained several others in connection with the case.

“The device performed exactly as it had been designed to do,” the inventor of the capsule, Philip Nitschke, told the Daily Mail, noting that it provided “a non-drug, peaceful death at the time of the person’s choosing,”

The deceased woman reportedly had been suffering from a severe illness that involved significant pain and had expressed a desire to die for at least two years.

“The woman had been suffering for many years from a number of serious problems associated with severe immune compromise,” the organization said. Mr. Willet was the only person present at the time of death.

Following the suicide, police, including forensic teams, arrived at the scene after being notified by a legal firm. The Sarco capsule was seized, and several people in the Merishausen area were taken into custody.