KITCHENER, Ont. - A "clearly troubled" young man will plead guilty in the fatal stabbing of an elderly man attacked during his annual tradition of hand-delivering Christmas cards, his lawyer said Monday.

Trevor LaPierre, 24, was charged with first-degree murder in the death of Hunter Brown, 74, but his lawyer indicated in court Monday that LaPierre will plead guilty on Jan. 18 to second-degree murder.

Brown was stabbed on the afternoon of Dec. 15, 2007 with what police described at the time as an "edged weapon." The attacker fled, leaving the retired Bell Canada executive and beloved grandfather to bleed to death on his neighbour's driveway, undelivered cards at his side.

Witnesses described the assailant in the bizarre attack, which horrified and frightened the community, as being clad all in black.

The court had earlier ruled LaPierre was fit to stand trial, but lawyer Brennan Smart said his client has a history of mental illness.

"He's a clearly troubled man," Smart said outside court. "He's not well. He's very depressed."

LaPierre was arrested in late 2007 as he and his father were en route to a psychiatric ward. His family struggled for years before the attack to get their son help for his mental health troubles, Smart said.

"(They) became very frustrated with the lack of assistance they had, but at the same time one has to be fair," said Smart, who added psychiatric issues aren't like a "cold or a flu."

"They're very difficult to diagnose and there isn't always anything that can be done," he said.

"I think in the case of Mr. LaPierre they are still struggling to try to determine how best to deal with the psychiatric issues. I don't think it would be fair to foist any responsibility for this crime upon the mental-health system in Ontario."

LaPierre is "very remorseful" for his crime and the guilty plea brings hope he will get the treatment he needs, Smart said.

When the case returns to court on Jan. 18 for the plea and the sentencing hearing, the defence and the Crown will be making a joint submission that LaPierre serve his sentence at a centre in Kingston, Ont., for inmates with mental health issues, Smart said.

A second-degree murder conviction means an automatic life sentence. Parole eligibility can be set at anywhere from 10 to 25 years. Though she would not say what the Crown will be recommending, attorney Karey Katzsch said that is one issue on which defence and Crown disagree.

Psychiatric assessments have been done and will likely play a role in determining LaPierre's sentence as will victim impact statements, which Katzsch said Brown's family may read at the hearing.

As the second anniversary of Brown's death - forever linked to the holiday season - just passed, this is a difficult time of year for his family, Katzsch said.

LaPierre gave a full explanation of his motive for the attack to a series of psychiatrists, Smart said. That evidence will be filed in advance of the hearing.