Montreal police now say the death of a 17-year-old youth following an altercation in Côte-Saint-Luc Thursday night was a homicide. Police no longer believe the teen was killed while trying to rob a young woman.

Police initially said the 17-year-old fell and hit his head while he and a 15-year-old accomplice were trying to rob a 19-year-old woman in front of a condominium building at the corner of Westminster Avenue and Westover Road at about 7:45 pm.

"The first information we had was that it was a robbery gone wrong," said Const. Jean-Pierre Brabant, Montreal police spokesman. "That was based on the testimony of the woman."

But Brabant said investigators spoke to witnesses in the building who said it was actually an altercation involving four people.

"That fourth person [a 19-year-old man] was located today, and for now he's considered an important witness in the dossier," he said.

The 15-year-old boy was detained for questioning Thursday night and released.

He said surveillance video, as well as autopsy results, led police to believe the teen's death was a homicide.

"The fall was probably not the cause of death," said Brabant, who declined to elaborate further.

Teen's mother wants answers

The mother of the 17-year-old victim said she was told very little about how her son had been injured when she met police at the hospital.

She only learned of the initial robbery hypothesis later Thursday night, when a friend of her son's showed her a news article.

"It's not a finished investigation, but yet they were comfortable releasing that this child committed a robbery, and it's a robbery gone wrong," she said.

She said investigators later told her that police were treating her son's death as a homicide, even as the official story from police was still one of a botched robbery.

The mother is concerned that police may have jumped to conclusions about her son — who is black — and released information too quickly.

"I'm accustomed to hearing this for young black males," she said. "It doesn't feel like they were trying to really get the truth first and put it out."

"I think it was just like, 'Well, most likely this is what he is, and this is what most likely happened.'"

Police said it was the 21st homicide in Montreal this year.