Dozens of people came together Friday night in Calgary to pay their respects at a candlelight vigil for five people, including two young children, killed in a murder-suicide.

Some who showed up at the Dalhousie Mennonite Brethren Community Church said they felt compelled to attend because they needed somewhere to unleash their emotions over the gruesome event.

"If there is one thing that bonds folks, it's tragedy overall, specifically when it involves kids. They're the innocent ones," said David Corriveau.

Insp. Guy Slater of the Calgary Police spoke to the media on Friday. (Larry MacDougal/Canadian Press)

Police said on Friday that 34-year-old Joshua Lall repeatedly stabbed his basement tenant, then went upstairs and used the same knife to kill his wife Alison, 35, and two daughters, ages 5½ and 3½, before taking his own life.

The bodies of his wife and daughters were found in the upstairs master bedroom of the house in northwest Calgary on Wednesday. Lall's body was located in the room of his one-year-old daughter, who was found crying in her crib, unharmed.

Amber Bowerman, a 30-year-old magazine writer, appeared to be the victim of a surprise attack as there was no sign of a struggle, police said.

They said there were defensive wounds on Alison Lall's body, showing that she died trying to protect her children. Police said they believe the stabbings took place on Tuesday night.

"Every indication is that Alison fought to protect her children," said Insp. Guy Slater, commander of the major crimes section.

Friends and relatives quoted in media reports have said Joshua Lall, an intern architect at a local firm, was struggling with psychological problems and had been under stress as he prepared for his accreditation exams to be registered as a professional architect.

His father, Dominic Lall, told the Calgary Sun his son was distraught when he called him in Ontario a few days ago and spoke of having a "mental breakdown or something."