Anne Marie D’Amico

Image Anne Marie D'Amico. Credit... Tennis Canada, via Associated Press

Ms. D’Amico, 30, worked at the Canadian head office of Invesco, an investment management company based in Atlanta. Her family described her in a statement as the “definition of altruism.”

“She wouldn’t stop until she went the extra mile for others,” her family said.

Since the age of 12, Ms. D’Amico volunteered at the Rogers Cup, a professional tennis tournament played in Montreal and Toronto. Gavin Ziv, an executive with Tennis Canada, the sport’s governing body, told C.B.C. Radio that Ms. D’Amico started out with the tournament as a ball girl.

At the time of her death, she was managing a group of about 200 volunteers.

Dorothy Sewell

Ms. Sewell, 80, was also a sports fan, her grandson Elwood Delaney told the CBC.

“She loved her Maple Leafs; she loved her Blue Jays,” Mr. Delaney said referring to Toronto’s hockey and baseball teams. “I don’t think she ever missed a Blue Jays game.”

Mr. Delaney said Ms. Sewell, who had worked at Sears Canada, died while going to the bank. News of her death, he said, had produced a mix of “pure anger and then sadness” in him.