A former Alberta high school principal accused of having sex with one of his students has pleaded guilty to two of three counts of professional misconduct — having an inappropriate relationship with her, and having a romantic relationship with her.

In the same declaration, presented in an Alberta Teachers' Association disciplinary hearing Monday, Leonard Lethebe admitted to having sex with the girl. But he pleaded not guilty to professional misconduct on that third count because he believes she was not a student when their sexual relationship began.

Lethebe is a former principal of Mistassiniy School in Wabasca. The student at the centre of the allegations was 17 at the start of the relationship, between Sept. 2007 and Dec. 2008. She gave birth to a baby last March, the hearing was told.

The school's vice principal, Christine Guillion, told the hearing she quit her position in May 2008 after telling Lethebe: "I cannot work with you any longer, and I can't believe the things you are doing."

Guillon told the disciplinary panel she complained to the Northland School Division, but feels "they really didn't do anything."

Lethebe was placed on leave by the board in Oct. 2008, more than a year after his romance with the student began.

Lethebe was not present at the hearing Monday and has not hired a lawyer to represent him.

Investigation started a year ago

The ATA launched the investigation into the alleged misconduct a year ago after it received two complaints about Lethebe. The ATA received a third complaint in May 2009. Lethebe's membership in the ATA was suspended on June 16, according to ATA spokesperson Dennis Theoboldt.

"This was in response to a concern that the individual may be seeking employment in the province." Theoboldt said. " We believed that the allegations made were sufficiently serious that they warranted a suspension pending a full investigation and hearing."

When reached by CBC News by phone on Friday, Lethebe wouldn't consent to a taped interview.

"I'm not into sensationalism," he told a reporter. He also expressed concern about how the disciplinary hearing would affect the young woman and her family, as well as his own.

Lethebe is on the witness list for day two of his disciplinary hearing on Tuesday, but the ATA has been told he does not intend to show up.

If he is found guilty of unprofessional conduct, the Alberta Teachers' Association has the power to cancel Lethebe's teaching certificate and membership.

With files from Janice Johnston