Calgary police say they're investigating the possibility that a man whose body was found, along with four others, at the scene of an apparent domestic homicide may have been responsible for the deaths.

Calgary Police Insp. Guy Slater said Thursday it's looking more and more like a case of "domestic violence" -- but he stressed it would be a "disservice" at this stage of the investigation to categorically state the man was responsible.

Police haven't yet released the names of the victims discovered at the Calgary home, and have not released further details of how they died. But family and friends have identified them as Joshua Lall, 35, his wife Alison, also 35, two of their daughters and tenant Amber Bowerman.

Only one person remained alive in the house after the slayings -- a one-year-old girl whose crying prompted the discovery of the bodies.

Police earlier said they are investigating reports that Joshua Lall had called his parents days before his death to say he was suffering some kind of mental breakdown.

"(Were) there warning signs, pre-incident indicators? Was there sufficient help available for folks who may have seen events deteriorating, or if they were looking for help?" Calgary Police Chief Rick Hanson told reporters. "These have to be answered."

It was also revealed Thursday that Lall wasn't missed at work on the day his body was found because he had a "planned absence."

The chairman of the architecture firm where Lall worked as an intern said he was shocked to hear of the slayings.

Rob Adamson of the Cohos Evamy firm described Lall as "kind-hearted," calling him a "solid" member of the company for the past five years.

Shocked neighbours described Lall as a "loving" father. And a former teacher described him as a young man who "had everything."

"He was an outstanding student with a 90-95 per cent average all the time," high school teacher John Candiotto told CTV Southwestern Ontario. "(He was a) great athlete, well liked by his friends, had a great social life, too, (and) a great family."

After graduating from Catholic high school Our Lady of Lourdes in Guelph, Ont. 16 years ago, Joshua Lall earned a degree in occupational therapy at McGill University in Montreal. He then got a job as an occupational therapist at Freeport Health Centre in Kitchener, Ont., where he met his future wife, Alison.

The couple then moved to Calgary where he was to fulfill his dream, at the time, to help people with disabilities.

Alison Lall had been on maternity leave from her job as an occupational therapist at the time of her death.

"They were a warm and caring family," neighbour Jerry Hauge told CTV's Canada AM on Thursday. "They really cared about each other and all the neighbours up and down the street," said Hauge, who is the president of the Dalhousie Community Association, which houses a kindergarten program that was attended by one of the slain children.

He said Joshua would often offer help on architectural matters to the association.

The tenant, Amber Bowerman, was the publications editor at the SAIT (Southern Alberta Institute of Technology) Students' Association's weekly newspaper.

Ian Busby, a friend of Bowerman, described her as someone who carried the "light of life" around with her. "She was one of those people that when she walked into a room, everybody knew it because she had a great smile on her face. She was always laughing," Busby told CTV News.

Police are working in the family's northwest Calgary home trying to uncover clues that could help explain the grisly murders.

A family acquaintance arrived at the home Wednesday morning and found the bodies of the girls, ages four and six, and the three adults.

Their bodies were found scattered throughout various rooms of the house.

Hanson said Thursday that investigators will be trying to piece together what happened in the days and hours before the murder. They are also trying to determine whether anything could have been done to prevent the deaths.

Police had not been called to the house for any previous domestic incidents.

Many of the officials who dealt with the crime scene have sought counselling. Some are referring to the deaths as Calgary's worst mass murder in 20 years, said Marks.

Police expect autopsy results to be released Friday.

With reports from CTV Calgary's Chris Epp and CTV Southwestern Ontario's Nicole Lampa