MONTREAL—A West Island man is on trial after an accident killed a 73-year-old woman and severely injured her husband only steps away from their home in Dollard-des-Ormeaux.

Yvan Grandmaison is charged with impaired driving causing death, but the case is far from being open and shut.

The tragedy took place a year ago as Ngan Wong Lee and her husband Poom Huy Shuy were walking home one night when they were struck from behind by 41-year-old Grandmaison.

Lee died from her injuries; her husband is still in hospital 12 months later.

Grandmaison's alcohol level was within the legal limit, however police tried other tests like asking him to walk on a straight line. Or stand on one foot. An investigator told the court today that he failed both tests.

Toxicologist Nathalie Goudreault testified that she found illegal drugs in a urine sample: cocaine and methamphetamine, better known as speed. Grandmaison's urine also contained a large amount of an antidepressant called Seroquel, the medication is also used a sleeping aid, however it causes drowsiness and even dizziness.

The prosecution believes the combination of drugs with the alcohol provoked the accident.

But despite the damning evidence, the defence was able to poke serious holes in the prosecution's case. For example, the toxicologist said the cocaine was likely taken several hours before and the amount of methamphetamine in the urine was so small, it might have been consumed the day before. The anti-depressants also didn't come with a specific warning against driving.

The defence was also able to point out that the elderly couple was walking on the street and not the ice-covered sidewalks. Police also confirmed that two lamp-posts on the street were defective, making it very dark

Late Wednesday afternoon the defence announced it would call Grandmaison to testify as a witness, he is expected to take the stand Thursday.