The first woman went missing in March.
Then, over the course of two weeks in May, three more women disappeared from the streets of Winnipeg, the capital of the western province of Manitoba.
This week, the police said a man already in custody had been responsible for killing all four, three of whom were members of Indigenous groups. The fourth woman, whose identity has not been established, is also believed to have been an Indigenous person, the authorities said.
The man, Jeremy Anthony Michael Skibicki, 35, had been arrested in May and charged in the death of Rebecca Contois, an Indigenous woman from Crane River First Nation, a reserve about 190 miles northwest of Winnipeg.
On Thursday, the police said they had also charged him with murder in the three other disappearances, using DNA evidence to link the killings even though their bodies have not been found.
“It’s always unsettling when there’s any kind of a serial killing,” Chief Danny Smyth of the Winnipeg Police Service told reporters on Thursday during a news conference.
The police did not provide a motive for the killings nor did they say how Mr. Skibicki had met the victims or if he had any connection to them before they disappeared.
The police believe Ms. Contois, 24, was the last woman to be killed. Her remains were found on May 16 in a dumpster behind an apartment building in Winnipeg. Mr. Skibicki was arrested two days later.
Another woman, Morgan Beatrice Harris, 39, was killed around May 1, and a third, Marcedes Myran, 26, was killed around May 4, the authorities said. Both victims were from Long Plain First Nation, a reserve about 55 miles west of Winnipeg.
The unidentified victim was believed to have been in her mid 20s and was the first woman who disappeared. The police released an image of a black jacket similar to the one she was wearing at the time she vanished in an effort to get tips from the public about who she might be.
“There is rage, despair, disgust, and unspeakable sadness as I think about the horrific and ongoing violence towards our women,” said Nahanni Fontaine, a member of Manitoba’s legislature, in a statement posted on Facebook. “No one should rest easy today.”
The murders in Winnipeg are another troubling episode in a country where the killing and disappearance of Indigenous women was called a “genocide” by a national inquiry that released a report three years ago on the issue.
Winnipeg, a city of roughly 750,000, has the largest population of Indigenous people of any Canadian city, according to government data.
“As a city, we must all grieve their loss and recognize that we have much more work to do, more work to do to protect the lives of Indigenous women and girls,’’ Scott Gillingham, the mayor of Winnipeg, told reporters on Thursday.