A sentencing hearing is being held in the case of a teen who pleaded guilty to second degree murder in the stabbing death of 49-year-old Larry McDonald.

The male, who was 16 at the time of the murder, entered the plea last week in connection with the March 2010 killing.

McDonald was stabbed nearly 20 times when he tried to break up a fight at his apartment on Green Valley Drive in Kitchener. He died shortly afterwards in hospital.

Whether a key piece of evidence, the statement given to police by the accused the day he was arrested, is admissible has not yet been decided.

A detective was testifying about that statement on Wednesday and it appears that at the time officers didn't properly read the accused his rights.

Crown attorney Cynthia Jennison says "Unfortunately there was just a minor imperfection in the provision of that and as a result there's an argument about whether or not that affects our ability to use it at the sentencing hearing."

The judge in the case must also still decide if the accused will be sentenced as a youth or an adult, so a psychiatric assessment has been ordered.

Defence lawyer Craig Parry says "That will help inform the judge as to how to sentence the person."

The psychiatric assessment is expected to be done on June 6th.

Meanwhile court will continue to consider the admissibility of all or part of the statement to police on June 4th.

With all the elements involved, the sentencing hearing may be longer than usual, with a final decision expected in the fall.