A killer has driven the streets of a Canadian city for five hours and shot at homeless people, killing two and critically wounding others.

Police in Langley, a town southeast of Vancouver, stopped the gunman by shooting him dead after the man attacked his final victim on a city bypass.

The suspect was known to police but officers said they did not yet know the motive for his attack. They did confirm it was targeted.

City of Langley Mayor Val van den Broek said at a press conference on Tuesday morning (Australian time) she was speaking with a “heavy heart”.

“My heart breaks. This is something that you never want to see happen in your community. Never, ever,” Ms Van den Broek said.

“I volunteer with the homeless and I know them and it’s very personal for me as well.”

Royal Canadian Mounted Police have set up at least five crime scenes, kilometres apart, around Langley.

One man was shot outside Creek Stone Place transitional housing. Photo: Stepping Stone Community Services

It appears the killer targeted people near a casino around midnight and then opened fire outside a social housing service at 3am. One man was found dead in the carpark of Creek Stone Place, a block of units for people transitioning out of homelessness.

Another man was killed at a bus stop about 5am.

The woman who was critically wounded was picked up from the side of a road and taken to hospital.

The last shooting occurred around 5.45am on a city bypass route, where police closed in and shot the gunman.

Kim Snow, a homeless advocate with Kimz Angels, told Global News the two people who were killed had been homeless.

“They are suffering souls, they are just people that need a place to live, they need chances, they are not on the street by choice,” Ms Snow said.

Police said it was too early to confirm the victims’ identities as they were still notifying family.

Langley residents had been stunned early in the morning when their phones blared with alarms warning them an active shooter was on the loose in the area.

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Questions are now being asked about why it took police so long after the first shooting, which was around midnight, for the public to be notified.

Authorities have also been asked how they could better use the alert system to protect vulnerable people who may not have access to mobile phones.

The city mayor said the alert process would be reviewed.

“If we can just save one person from getting injured…I think it’s better for all of us,” Ms van den Broke said, noting that it was the second time the city had used the text system.

“God forbid we should have to use it again.”

She said the community needed to do more to protect people who had mental health or substance abuse issues and for people struggling to put a roof over their heads.

“We need more federal funding to address the issues that are going on, we need to see facilities built,” Ms van den Broek said, adding “maybe this is the catalyst”.

Fighting back tears, the mayor recalled how she had had to turn away people who had begged her for help to find housing in a region she said had a disproportionate number of rough sleepers because of its relatively warmer climate.

“In my heart this is something I care very deeply about. Honestly, I’m just heartbroken this morning,” Ms van den Broek said.

“I know I know some of the people involved.”

In an alert sent to British Columbia residents, police had said the shootings involved “transient victims”. It said the suspect was described as a white man in overalls and a camouflage t-shirt.

A second alert at 7.22am (local time) said the suspect was “no longer a threat”.

Parts of the city remain closed as the investigation continues.