A former Queen’s chemistry PhD candidate pleaded guilty to two charges last Thursday and admitted to poisoning his former roommate and colleague with a lethal substance.

The plea comes after 26-year-old Zijie Wang was arrested by police on campus and charged earlier this year. In a courtroom on Oct. 25, Wang pleaded guilty to administering a noxious substance, to endanger life or cause bodily harm, and to a charge of aggravated assault.

When Wang sat in front of Justice Allen Letourneau last Thursday, the victim, a member of Wang’s former research group, was a few feet behind him in the gallery.

On Jan. 29, the day of Wang’s arrest, he was videotaped in his lab coat using a pipette to administer a “clear substance” into the victim’s lunch on campus. The substance—later identified as N-Nitrosodimethylamine (NDMA)—is highly toxic and a known carcinogen.

After a toxicology report identified the substance, Wang was charged with aggravated assault and criminal negligence causing bodily harm. Since his second arrest on April 12, Wang has been in custody awaiting trial.

The first incident of poisoning took place on Jan. 8 of 2018, when the victim brought an apple pie to the chemistry lab where he works on campus.

When the victim took a first bite of the pie, he found it was “bitter-tasting.” He then tried a second bite, but “found it was too bitter to eat.” Four hours later, the victim became ill with diarrhea.

At the time, the victim had to put his head down on his desk, feeling nauseous before  vomiting.

A week later, on Jan. 15, the victim brought another pie to work. The victim believed the pie he’d eaten the week before had been contaminated when he bought it from Metro .

When the victim first tried the pie, it tasted normal. But when he reached the middle of the pie, he found it tasted bitter—similar to the last pie. He didn’t become ill after that incident.

The next Monday, on Jan. 22, the victim brought cinnamon raisin bread bought from Loblaws to work. The victim kept half the loaf in his fridge at home and brought the other half to the lab.

When he ate the loaf he’d kept in the lab, it had the same bitterness he’d tasted in the pies the last two weeks. The victim then asked a colleague to try some of the loaf. The colleague spat out the bread and agreed it didn’t taste right.

The victim brought the poisoned bread home to compare it with the half he’d left in the fridge. The victim noticed the subtle difference in the odours of the two halves and determined one was contaminated.

In January, the victim drove home to Mississauga to be with his wife and children. During his drive home on Jan. 19, and Jan. 26, he noticed a chemical taste in his water.

He had his colleague smell the water, who agreed it wasn’t natural.

The victim approached his research supervisor with his concerns, who advised him to video record the next potential poisoning.

On Jan. 29, the victim set up a motion-activated webcam on his desk in the chemistry lab. He took a picture of the inside of his backpack, which contained a loaf of bread, and placed the bag in the front drawer of his desk.

Wang left a group meeting at 8:56 a.m. and didn’t return until 9:53 a.m. The victim’s video recorder, set up in a different room, later revealed Wang had been poisoning the loaf of bread during this time.

The victim and his research supervisor reported the poisoning to Dr. Hans-Peter Loock, head of the Queen’s chemistry department. Loock contacted campus security, who then called the police.

The victim had kept two containers of the pies and bread and samples of the water “he believed to be poisoned.”

Though Queen’s labs don’t stock NDMA, Wang had access to the chemicals needed to create it himself. A motive wasn’t revealed at the plea hearing last week.

Wang’s sentencing hearing is scheduled for Nov. 2.