CALGARY - Joshua Lall surprised his basement tenant with a knife Tuesday night, stabbing her repeatedly before going upstairs to kill his wife, two young daughters and eventually himself, Calgary police confirmed late Friday.
What police couldn't possibly explain about the horrific murder-suicide - that left everyone in the house dead except for a one-year-old baby girl - was why.
"I can't even speculate on that. The only person that knows that is Joshua himself," Insp. Guy Slater said late Friday afternoon after autopsy results were released.
Despite outward appearances of a happy and devoted husband, father and architect in training, speculation since the bodies were found Wednesday has centred around Lall's mental health.
The police said Friday they would leave that up to mental health professionals, but said there was no suicide note, no obvious drug or alcohol use and apparently no warning.
It appears that Tuesday evening at the family's house in a quiet, north Calgary neighbourhood started out "like any other evening," Slater said.
But at some point Lall, 34, took a knife and began to kill, inflicting multiple wounds on all his victims.
Basement tenant Amber Bowerman, a 30-year-old freelance journalist in Calgary, was the first to die in the surprise attack.
"There is nothing to indicate that Amber could have done anything in her situation," said Slater.
Lall then went upstairs and found his family cowering in the master bedroom, where police later found a scene so disturbing that all responding officers and EMT personnel were given immediate trauma counselling.
His wife Alison, 35, had defensive wounds that suggested she fought hard - and in vain - to save her daughters. The bodies of three-year-old Rochelle and nearly six-year-old Kristen were found near their mother.
"Every indication is that Alison fought to protect her children," police said.
Afterward, Lall stabbed himself. Strangely, his body was found on the floor of the baby's room where the little girl was found in her crib untouched.
"We can't speculate on what his thoughts were at the time," said Slater. "We do know that we found him deceased on the floor in that room."
Published media reports quoted sources saying that Lall had expressed fears he was possessed by the Devil and was hearing voices.
His father, Dominic Lall, told the Calgary Sun he received a frantic call from his son just days ago, and that he and his wife were scheduled to fly from their home in Guelph, Ont., to Alberta to check on their welfare. Tragically, their flight arrived in Calgary one day too late.
But Lall's boss at a Calgary architectural firm said there were no outward signs that anything was wrong.
"I saw (him) on Friday afternoon last week before the weekend and ... we had a very enjoyable end-of-the-week conversation about what we each were going to be doing on the weekend with our families, and about dinner reservations at restaurants that he was hopeful to make," Rob Adamson of the architectural firm Cohos Evamy said Friday.
"It was a total surprise to me that there's allegations or suggestions that Joshua had some significant mental health issues."
He said there were no indications from any of the other 175 employees that anything was wrong.
"He was extremely popular. Joshua was a friendly, outgoing guy. He was helpful to everybody and probably touched everybody in some way in our office."
A candlelight vigil for the victims was planned at a Calgary church Friday night.
In Ariss, Ont., where Alison Lall grew up, friends recalled her fondly.
Astrid Van Den Broek described her as "giving, patient and kind" and a hard worker who took on several responsibilities on different committees.
Mary Law, who was Alison's professor, called her a "quietly confident and exceptionally talented" student.