Vicky Shachtay was at home Friday morning with her caregiver when a package was delivered to her door. Later that morning, when she began opening it from her wheelchair, it exploded, killing her and mildly injuring her assistant, the RCMP said.
The explosion happened in the town of Innisfail, about 70 miles north of Calgary and struck fear through its 8,000 residents, the National Post said.
Autopsy results were still pending Tuesday, the Calgary Herald said.
The RCMP brought in an undisclosed number of investigators from Ottawa, including some with ordnance experience in Afghanistan, the Toronto Star said.
"Physical evidence at a scene is dispersed over a wide area and quite a bit destroyed," Sgt. Patrick Webb told reporters. "We have a witness, the caregiver was there, but we're not going to put out certain details unless it serves the investigation."
Shachtay lost the use of her legs in a car accident while she was pregnant with her now 7-year-old daughter, who was at school when the bomb exploded, the reports said.