William Melchert-Dinkel
William Melchert-Dinkel denies being responsible for anyone's suicideReuters

A US nurse who disguised himself as a suicidal woman to encourage people to kill themselves online has had his conviction reversed.

William Melchert-Dinkel, 51, was convicted of two counts of aiding suicide in 2011 after a judge ruled he had "intentionally advised and encouraged" 32-year-old Mark Drybroug from Coventry and 18-year-old Canadian Nadia Kajouji to take their own lives.

Drybroug hanged himself in 2005 after Melchert-Dinkel posed as a suicidal woman and befriended him online. Kajouji of Brampton, Ontario, died after jumping into a frozen river in 2008.

Melchert-Dinkel, from Faribault, Minnesota, was sentenced to 360 days in prison. However, his sentence was put on hold while he appealed and he remained free while the process was pending.

The Minnesota Supreme Court has reversed his conviction after it ruled that the state's law which forbids advising or encouraging suicide is too broad and uses speech protected by the First Amendment.

His lawyers argued that merely encouraging suicide – rather than assisting it – is protected by law under free speech. As the judge in the original case did not did not issue a ruling on assisting suicide, the conviction has now been reversed and the case referred to a lower court.

In 2011, Melchert-Dinkel told police he posed as a woman online and entered suicide pacts with people for "thrill of the chase".

Elaine Drybrough, Mark's mother, said: "What Melchert-Dinkel did was immoral but whether or not it's illegal is another matter and is to be decided by the courts.

"I don't think anyone would be able to do what he did, and the way he did it, today.

"He was doing it continuously from the time he was speaking to my son and Nadia. He'd been doing it for years before their deaths, probably because he enjoyed it."

Deborah Chevalier, Kajouji's mother, added: "It's a legal system; it's not a justice system. The two are completely different.

"At the very least, the world knows what he's done. His friends, his family know what he's done. He can't run away from that."

According to court documents, Melchert-Dinkel spoke online with up to 20 who were considering suicide and agreed to enter suicide packs with 10, five of whom he believed killed themselves.

The court must now decide if Melchert-Dinkel had "assisted" in the suicide of Kajouji and Drybroug. He claims he did not encourage the pairs actions and simply offered the pair support.