Erin Riley-Oettl was a teenager when Constable Stevenson arrived at her troubled high school in the late 1990s as a liaison officer.

Image Constable Heidi Stevenson of the Royal Canadian Mounted Police. Credit... Rcmp/The Canadian Press, via Associated Press

Cole Harbour District High School in Halifax, Nova Scotia’s largest city, had been buffeted by race-related brawls. Ms. Riley-Oettl said Ms. Stevenson became an effective mediator, a mentor for young women and the coach of her rugby team. She took the time to get to know the students and became such a part of the school community that she married the gym teacher.

“She became a mentor and older sister for a lot of students and members of the rugby team,” said Ms. Riley-Oettl, who is now a lawyer in Toronto. “It was an inspiration for us girls to see a strong woman who was a police officer and a former rugby player.”

“She was a role model,” Ms. Riley-Oettl added.

Lillian Hyslop, another victim of the shootings, had moved to Wentworth Valley, an area of Nova Scotia with a small ski resort, after the retirement of her husband, Mike. They had left the northern chill of the Yukon Territory for the comparatively balmy maritime climate of southern Nova Scotia.

She was taking a walk when her neighbors were calling each other to relay police warnings to stay inside and take cover because of the shootings.

Fire officials said she was killed on the roadside.

With victims not yet officially identified, some families remain uncertain about what happened to their loved ones, with some told only that they are missing and others told nothing.