TORONTO - The father of a missing Toronto teen will undergo psychological testing before he's sentenced for stabbing three people.

Vakhtang Makhniashvili, 51, made a brief appearance in court today and is scheduled to return for a sentencing hearing on Sept. 9.

The Georgian immigrant pleaded guilty in May to three counts of aggravated assault related to two separate incidents last year.

Earlier this week, court heard a psychiatric report found Makhniashvili has a "major mental illness."

Lawyers for the Crown are asking for more tests in order to obtain a clear diagnosis.

Makhniashvili's daughter, Mariam, was 17 when she vanished in September 2009.

"The daughter going missing, it spawned a psychiatric reaction," defence lawyer Calvin Barry said outside court.

Makhniashvili admitted to stabbing two people in front of their home last November. They had posted his bail after he was charged with stabbing a neighbour at his apartment building in May 2010.

Court heard at the time that he thought the victims were either involved in his daughter's disappearance or behind an unflattering newspaper article.

Makhniashvili's sentencing was put on hold Tuesday after he told court he was pressured to plead guilty. But he later agreed to let the pleas stand.