CHICAGO (Reuters) - A former Minnesota nurse was charged on Friday with persuading a British man and a Canadian woman through an online chat room to commit suicide, lying to some prospective victims that he would die with them.

William Melchert-Dinkel, 47, of Faribault, Minnesota, may have watched at least one of his alleged victims die via webcam, telling police he had an “obsession” with suicide, according to a criminal complaint.

A former hospital nurse, Melchert-Dinkel was charged in state court in Rice County, Minnesota, with two counts of aiding suicide, and could face up to 30 years in prison.

The complaint named two victims: Mark Drybrough, 32, of Coventry, Britain, who hanged himself at his home in 2005; and Nadia Kajouji, 18, of Ottawa, whose body was found in a river more than a month after she went missing in March 2008.

Authorities said Melchert-Dinkel suggested to prospective victims how much rope to buy and how to tie a slip knot, or how best to drown themselves. He told police when they interviewed him that he advised people what they could expect to experience when hanging themselves, the complaint said.

He also admitted making suicide pacts with 10 or 11 individuals, characterizing his actions as “the thrill of the chase,” the complaint added.

A British woman who frequented the chat room warned authorities in March 2008 that a predator was active on the site, which is devoted to people who want to share suicidal thoughts and feelings of depression, the complaint said.

The woman told Minnesota authorities the predator, using the aliases “Li Dao” and “Falcon Girl,” posed as a “young, kind, sympathetic woman who worked as an emergency room nurse, and (was) encouraging people to commit suicide,” according to the complaint.

The complaint said Melchert-Dinkel told police he felt terrible about his role as an advocate for suicide, estimating he had helped “five or less individuals in killing themselves.”

“For anyone, much less a health care professional, to exploit another at their most vulnerable point in life is disturbing,” St. Paul, Minnesota, Police Chief John Harrington said in a statement.

Melchert-Dinkel, who has been ordered to appear in court next month, could not be reached for comment.