The trial of a Winnipeg man this week could determine if accused drug dealers can be held responsible for the deaths of those using their drugs.

Curtis Haas, 52, pleaded not guilty on Monday to two counts of drug trafficking and one count each of criminal negligence and manslaughter in the death of Wendy Henry, 20.

Henry was found unresponsive inside a Manitoba Housing apartment complex on Dufferin Avenue in the early hours of Oct. 28, 2007. It was determined that she had overdosed on morphine.

A security guard at the building testified on Monday that he found the woman lying on the floor in Haas's suite.

Haas was performing CPR on Henry, who was vomiting at the time, court was told.

The security guard also testified that Haas appeared upset and said Henry had gotten into his morphine.

Outside court, Henry's father, Glen Henry, told reporters the testimony has been difficult for him and other family members to hear.

At the same time, Henry said he's just relieved the trial has finally begun.

"With the cases that's going on — trials and pre-trials and etc. etc. — and listening to everything again is very stressful and taking time off work as a single parent, it's very hard," he said.

The trial is expected to last about one week.