A request by a convict behind bars for life is testing Switzerland's support for assisted suicide, raising complex questions over whether ill prisoners can seek help to end their own lives.

The unprecedented case has exposed a legal vacuum in the country which has long been at the forefront of the global right-to-die debate. An official decision is due in the coming months.

"It is natural that one would rather commit suicide than be buried alive for years to come," prisoner Peter Vogt said, in a written response to questions submitted by the French Press Agency (AFP).

The 69-year-old, convicted for sexual assault and rape against multiple girls and women ranging in age from 10 to 56, says he is suffering from serious kidney and heart conditions, among other ailments.

He has also been diagnosed with several psychological disorders.

This follows a decision in 2004 when Swiss voters approved a popular initiative allowing the indefinite detention of people with established sexual delinquencies who posed a public risk.

The authorities have repeatedly determined that Vogt remains a threat despite years of treatment.

In July 2018, Vogt contacted Exit Switzerland, an organization that supports assisted suicide under specific conditions. He argues that he should be able to benefit from Switzerland's liberal assisted suicide laws too.

Swiss law generally allows assisted suicide if the person commits the lethal act themselves, meaning doctors cannot administer deadly injections, for example, and the person consistently and independently articulates a wish to die.

Organizations that support assisted suicide also apply their own procedures, which are more robust than the legal requirements.

In October, the experts at the foundation advised that assisted suicide rights should apply to prisoners under certain conditions, noting that in cases of mental illness two independent specialists should be consulted.

Vogt insisted that he wanted to die because of the "unbearable" deterioration in his quality of life, along with the fact that he can no longer see his gravely ill mother, who lives in Austria.

He told the Blick newspaper that he wants to end his life on Aug. 13, his 70th birthday.

Some have raised concern that assisted suicide requests could be used by convicts as a negotiating tactic to demand better conditions in prison.

For Christine Bussat, founder of the Swiss chapter of the Marche Blanche victims' rights group, decisions on a convict's right to die should rest with their victims.

That, she added, "is unfortunately not possible" under the current law.

But most legal and criminal justice experts in Switzerland believe that assisted suicide rights do extend to convicts.

Celine Ehrwein, an ethics professor at Heig-VD University, told public broadcaster RTS that depriving a suffering person of the right-to-die could be considered "a form of torture."