Toxicologist testifies at sex assault trial of former Halifax taxi driver

The sex assault trial of a former Halifax cab driver heard Friday from a toxicologist who said the complainant's urine had elevated levels of acetone, which can come from "exposure to a stressful situation."

Christopher Keddy, an RCMP forensic toxicology specialist based in Ottawa, testified via video on the seventh day of Bassam Al-Rawi's trial in Nova Scotia Supreme Court in Halifax.

Al-Rawi is accused of raping a woman in his apartment in the early morning hours of Dec. 15, 2012. The 35-year-old complainant has testified she drove to Halifax from Pictou County on Dec. 14, 2012, with a group of friends. She testified she was assaulted while she was highly intoxicated and pretending to be unconscious.

This is the second time Al-Rawi has been charged with sexual assault in Halifax. Last September, he was found not guilty in a retrial of a case that gained national attention and involved accusations he sexually assaulted a woman in his cab in 2015.

Keddy testified that the complainant's urine sample from the sexual assault nurse examiner kit taken at 8:15 p.m. on Dec.15, 2012, was analyzed by a colleague of his in a March 2013 report. Since that person has retired, Keddy took over the file and went over the analysis again, coming to the same conclusions.

Substance could have been caused by 'stressful situation'

Keddy said ephedrine was found in the urine, which is a drug that stimulates the brain and parts of the body. It's a naturally occurring drug found in some plants and health products used for weight loss. He added he's seen ephedrine in products used by weightlifters trying to lose fat, which can be found in supplement stores.

The complainant has said she was using a workout supplement in the months before the alleged assault in the form of protein powder.

Higher than usual levels of acetone were also found. Acetone occurs naturally in the body, Keddy said, but can spike due to conditions that increase fat burning like a keto diet, fasting, obesity, or "exposure to a stressful situation."

Keddy could not say what caused that heightened acetone, or when it began, since it would accumulate gradually and not be a "switch on, switch off" event.

The urine sample tested positive for cannabis. Keddy said it usually shows up within one hour after use, lasting until about 12 to 24 hours later in an infrequent cannabis user.

The complainant has testified she was not a regular cannabis user, and had two drags of a joint Al-Rawi rolled for them.

When asked if Keddy could tell how much cannabis was used or smoked in this case, he said that's an "'impossible question" to answer because it's present after recreational use and that amount varies from person to person. He also could not say when the cannabis was consumed.

Keddy said the urine tested negative for alcohol.

Crown attorney Carla Ball outlined a scenario where the complainant's urine was collected the evening of the alleged sexual assault, and went over what she drank over Dec. 14-15 — unknown drinks with lunch, followed by multiple beers and shared pitchers over the night — as well as the woman's height and weight.

Calculating blood alcohol level

Keddy was asked if he could calculate what the woman's blood alcohol level would have been between 2:30 a.m. to 4 a.m., when the alleged assault took place, but he could not provide a "reasonable estimate" given the imprecise amounts of alcohol.

Ball asked more broadly if a woman of the complainant's description could eliminate "a lot" of alcohol within 16 hours, which was the time between the alleged assault and the urine sample being taken. Keddy said it could be possible, but he couldn't say for sure without more information.

He then added that the "vast majority of people" could eliminate 160-320 milligrams of alcohol per 100 millilitres of blood over that time.

The legal driving limit is 80 milligrams of alcohol per 100 millilitres of blood, or .08 per cent.

The trial continues Monday.