A 27-year-old woman who was pulled from a house fire in the Dufferin Grove area on Wednesday died as a result of a homicide, Toronto police said.

Det. Sgt. Mike Taylor of the homicide unit provided an update Friday on the investigation into the fire that broke out at a two-storey home on Rusholme Rd, in the area of College Street and Dovercourt Road, shortly after midnight.

He said fire crews found Jessica Perez Ocampo and Roberto Mendez, 27, in the basement of the home and rescued them. Ocampo was pronounced dead at the scene, while Mendez was transported to the hospital in critical condition.

Taylor revealed on Friday that Mendez had died.

The homicide detective would not disclose Ocampo's cause of death but said she sustained "some trauma" to her body.

"It is believed that Roberto is responsible for the death of Jessica Perez Ocampo," Taylor said.

"Again, it's very early on in this investigation, but what I wanted to say is that this is not a random act. This was an isolated incident, and we are continuing to investigate that."

Taylor said Mendez and Ocampo were in a relationship.

"To the extent of how their relationship was, it is a little hard to determine right now as we speak, but I know from speaking with people that they were in a relationship," he added.

The homicide detective noted that Mendez resided in the home and Ocampo did not. He said Mendez was not known to police.

Meanwhile, the cause, origin and circumstances of the fire are still unknown.

Toronto paramedics previously said three other people were taken to the hospital from the fire scene. On Friday, Taylor clarified that those individuals tried to help Mendez and Ocampo escape the basement.

"Unfortunately, they couldn't help to that extent, but they did the best they could at that time," he said.