William Melchert-Dinkel, the Faribault nurse described by officials as having a "suicide fetish," was charged in Rice County on Friday of aiding suicide.
Police say he developed online relationships with Mark Drybrough, 32, of Great Britain, and Nadia Kajouji, 18, of Ottawa before they killed themselves.
Drybrough hung himself in 2005. Kajouji's body was found in a river in 2008.
Police began investigating Melchert-Dinkel in 2008 after a tipster notified the Internet Crimes Against Children (ICAC) Task Force, based in St. Paul.
Melchert-Dinkel was using aliases such as "falcongirl" and "Cami" to communicate with people using suicide chat rooms, the tipster said.
As the probe moved forward, the Faribault Police Department, the Ottawa Police Service in Canada, the West Midlands Police in Britain all became involved. British and Canadian news media also delved into the case.
Here's more from The Toronto Star on Kajouji:
Ottawa police had disclosed to Kajouji's father that Cami had been in contact with his daughter, and had given him dozens of pages of online chats, which Kajouji's family shared with the Star.
"If drowning doesn't get me, hopefully the hypothermia will," Kajouji confessed to Cami, an online confidant also planning a suicide, just days before her death last March.
"I'm planning to attempt this Sunday."
Cami encouraged her to hang herself in front of a webcam instead.
"I can help you with it," Cami promised. "Proper positioning of the rope is very important."
And from the U.K.'s Daily Mail, which spoke to Drybrough's mother last year:
'Mark had had a nervous breakdown and he was depressed and incredibly susceptible. This person was there whispering in his ear every time he logged on. In the last email, this person claimed to be a nurse, saying he had medical training, and proposed a suicide pact.
'We reported it to our local police straight away. I gave them the emails, but I didn't hear anything back until I was contacted by police from Minnesota, who said they expect to make an arrest in two weeks.'
Mrs Drybrough said the British police continued to show no interest in the case. She eventually tracked down Mr Melchert-Dinkel with the help of a Wiltshire youth worker, Celia Blay, who discovered that dozens of people had received similar emails to Mark's.
Fox 9 has reported there may be more victims:
Melchert-Dinkel said his wife had nothing to do with it, and admitted to using Google and a suicide method website to enter into 10 to 11 suicide pacts with individuals all over the world. He said Nadia Kajouji died after jumping into a frozen river, and admitted he played a larger role in her death than he originally let on.
The Star Tribune reports that Melchert-Dinkel, who lives with his family in Faribault, was charged by summons and is not in custody. His first court appearance is scheduled for May 25.