An infant boy who died after an early morning arson fire on Tuesday was the victim of a homicide, police say.

The boy's 29-year-old mother remains in hospital with life-threatening injuries. Homicide detectives and the police arson unit continue to investigate.

No suspects have been arrested, police said in a news release late Tuesday afternoon.

Eight people, including three children, were in the house at 1040 Armitage Crescent when the fire broke out just before 4 a.m. Fire crews arrived quickly and police were called to the scene "minutes later," the news release said.

All eight residents were treated and transported to hospital, police said. The five-month-old boy died later in hospital.

Hunter

Five-month-old Hunter was killed in the house fire and is Edmonton's 32nd homicide victim of 2017. (GoFundMe)

Police did not identify the boy, but a GoFundMe page identifies him as Hunter.

Kyle Whitford, who lived in the basement of the house with his roommate, said he was awakened by fire alarms, and at first thought someone upstairs had burned some toast.

Whitford said they went upstairs to check.

"The whole front entrance was just lit up, like bright glowing orange," he said. "We went back downstairs, got our kids."

He said by that time there was too much smoke in the back entrance, so they escaped through a basement window.

Scott Macdonald, deputy chief of operations for Edmonton Fire Rescue Services, said flames and smoke were visible from outside the home when firefighters arrived at about 4 a.m.

"We had reports of two people trapped inside, so we were able to pull out two people from inside and work on them and they were transported to hospital," Macdonald said in an interview from the scene. 

"They were upstairs on the second floor and our crews did a really good job getting them out. The crews were actually inside and got them out down the stairwell."

The flames were extinguished before 6 a.m. but fire crews remain on scene dousing hot spots.

The house was gutted in the blaze. There is no estimate on the total cost of the damage.

'Totally engulfed in flames'

Robert Bishop, who lives four houses down on the same street in southwest Edmonton, said a muffled scream for help woke him up at 4 a.m.

Seconds later, Bishop heard sirens, smelled smoke, and looked out his bedroom window.

Robert Bishop

Neighbour Robert Bishop says he could see flames shooting over the top of rooftops. (Nola Keeler/CBC)

Though the home was out of view, he could see the flames shooting over the top of the rooftops.

Then he spotted someone "tightrope-walking" across the top of his neighbour's fence, away from the property.

By the time he made it out onto the street, fire crews had arrived. 

"The house was totally engulfed in the flames. As I was walking down the street, the firefighters were just getting water on the home. As you can see now, it's a total loss." 

The circumstances of the fire were unsettling, he said.

"I heard they were trapped in the back of the house and couldn't get out," he said. "It's a very sad situation."

A search of land title certificate lists the registered owner of the home as Angie Tang.

Whitford said Tang and her husband, Cordell Brown, and their infant son lived on the second floor of the house. A man lived on the main floor.

The boy's death is the city's 32nd homicide of the year.

House fire crescent

Firefighters were able to rescue a mother and her child from the upper floor of the Ambleside home, but the infant boy later died. (Nola Keeler/CBC)