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Around this time last year, Timothy Dingwall was celebrating a hockey championship and starting down a path toward becoming a high school principal.

Dingwall, 40, was charged Thursday with sexual exploitation after weeks of investigation. He is currently on paid leave and is scheduled to appear in court on June 10.

The popular history and geography teacher at Harbord Collegiate Institute last year coached the senior boys’ hockey team to the city high school championship. A few months later he would complete part 1 of Ontario’s principal’s qualification program.

But rumours about an inappropriate relationship with one of his students started to swirl through the school’s hallways a few weeks ago, when Dingwall, who was also the head of the history department and boys’ baseball coach, was abruptly removed from the classroom and replaced with a substitute.

“He was a good teacher, confident,” said a Grade 12 student, who played on the winning hockey team coached by Dingwall but asked that his name not be published. “He was somebody you could talk to, but still a serious teacher.”

Police would not elaborate on the alleged relationship between Dingwall and the 17-year-old girl, but a charge of sexual exploitation involving older teens only applies when the perpetrator is considered to be in a position of trust or authority.

Gossip was flying online and in the schoolyard Tuesday, but a group of Dingwall’s students said they were concerned about their former teacher and what will become of their classes now that he’s gone.

“We lost a really great teacher at our school,” added a Grade 12 female student, who said she was in Dingwall’s class.

The school board would not say how long Dingwall had been teaching at Harbord, but according to the Ontario College of Teachers website and other online profiles, he was certified in 1997 and has been teaching in Toronto for 12 years, including time spent at Richview and Lakeshore Collegiate Institutes.

According to an online interview on a history studies website, Dingwall, who also started a Genocide and Crimes Against Humanities elective course for Grade 11 students, said his mother fostered a strong sense of social justice in his family and made him aware of how much good could come from working with young people.

At Dingwall’s home Tuesday afternoon, a woman who answered the door with a baby in her arms, refused to make Dingwall available for comment.