A former nurse in Minnesota who encouraged an English man and a Canadian woman to kill themselves by chatting with them on the internet has been sentenced to almost a year in prison.

William Melchert-Dinkel, 48, will spend 360 days in jail having been found guilty in March of aiding suicide. Evidence provided to the judge that posing as a female nurse he had communicated with up to about 20 people on suicide chat rooms.

He had also entered into suicide pacts – never intending to keep his side of the deal – with 10 people.

In the two counts presented to the court, Melchert-Dinkel was found to have encouraged Mark Drybrough, 32, from Coventry to kill himself in 2005, giving him tips on how to do it. He also aided the 2008 suicide of Nadia Kajouji, 18, from Ontario.

In that case, he had taken on the persona of a young woman called Cami who appeared on the chat sites. As "Cami" he befriended Kajouji, entering into a suicide pact with her: they discussed several possible ways of dying.

The prosecution told the judge that Melchert-Dinkel had an obsession with suicide and had revelled in the "thrill of the chase". On several occasions he had given advice to vulnerable people about the most painless and efficient way of killing themselves.

Defence lawyers argued that the two individuals who were involved in the charges brought against him had been intending to kill themselves in any case. Melchert-Dinkel's right to engage in conversations on chat sites was protected by the first amendment on freedom of speech, they said.

In deciding the sentence, the judge, Thomas Neuville, said Melchert-Dinkel's actions had been calculated and intentional and had deceived those he engaged with. He gave him much less than the maximum 15 years in prison partly because he said the defendant was not the only cause of the two individuals' deaths.

Melchert-Dinkel presented the judge with a statement in which he said he was filled with remorse.