OTTAWA -- A former Canadian soldier has been convicted of first-degree murder in the death of his wife.

Media reports say the jury handed down the guilty verdict on Thursday after deliberating for more than a week.

Lawyers for Howard Richmond, 53, had told an Ottawa jury that their client should be found not criminally responsible.

Richmond admitted to killing his wife with a knife and a screwdriver, but his lawyers argued he suffered from post-traumatic stress disorder.

He was diagnosed with the condition in 2011. He had served with the military in both Afghanistan and Bosnia.

Melissa Richmond, 28, was found dead near a ravine during the summer of 2013 after her husband contacted police about her disappearance.

Prosecutors contended that Richmond was upset because his wife was having an affair.

A first-degree murder conviction carries an automatic life sentence with no chance of parole for 25 years.