Supt. Jim Perrin of Halifax Regional Police said investigators believe the 26-year-old university student was slain on Feb. 13, the day she was last seen.
"I can't imagine what a tragic event this is for Ms. Saunders's family and friends and we're glad we're able to bring this to some sort of conclusion quickly," Perrin said.
Perrin wouldn't give any details of how Saunders died.
"I can't get into the evidence because now the case is before the courts," he said. "For first-degree murder there has to be some planning to the crime and our investigators are satisfied that existed."
Victoria Henneberry, 28, and Blake Leggette, 25, are scheduled to face the allegations against them in Halifax provincial court Friday.
Perrin said Henneberry and Leggette were in a relationship and they once shared the apartment with Saunders, though he could not say how long the three lived together.
When asked whether Saunders was killed at the apartment shared by Henneberry and Leggette, Perrin replied: "That's correct."
Henneberry and Leggette were charged earlier with stealing Saunders's 2000 Toyota Celica, which was found Feb. 18 in Harrow, Ont., south of Windsor.
Saunders's remains were found Wednesday at about 4:30 p.m. in the median off Route 2 of the Trans-Canada Highway west of Moncton, N.B.
Delilah Terriak, Saunders's sister, said the family had no comment Thursday.
The murder charges came hours after Henneberry was brought to court for a bail hearing on the theft charge. The matter was adjourned to give lawyers more time to review the case.
Before the murder charges were announced, defence lawyer Patrick MacEwen said outside court that the lawyers needed time since Henneberry had just arrived in Halifax late Tuesday after being arrested in Ontario days earlier. Halifax police said they spoke with her the next morning.
MacEwen had little to say about his client when asked how she was doing.
"She's in the same shape as anyone in her predicament is," he said. "She's in custody and I'm sure she doesn't want to be there."
Some of Saunders's friends and one of her brothers sat in the back of the courtroom for the brief hearing, but said nothing to reporters as they left the building.
Members of Saunders's family travelled to Halifax to make public appeals for help in finding the young Inuit woman, who was originally from Labrador. Dozens of supporters papered the city with posters showing a smiling Saunders and her bright blue car.
Terriak, 21, has said her sister was set to graduate from Saint Mary's University in May.
Cheryl Maloney, president of the Nova Scotia Native Women's Association, said she was heartbroken to hear the news of her death and the murder charges that followed. She had helped organize the poster campaign and a vigil in Halifax in the days before her remains were discovered.
"We were praying that this beautiful soul would be spared," Maloney said.
Maloney came in contact with the student when Saunders asked if she could interview her about native women who have been killed in Nova Scotia and elsewhere in Canada, which was the basis of her thesis proposal at Saint Mary's University.
"I've been thinking the last few days about the interview we had about missing and murdered aboriginal women and how dedicated and committed she was to having the issue raised," Maloney said.
National Chief Shawn Atleo of the Assembly of First Nations said Saunders's death brings focus on the need for a national commission of inquiry into missing and murdered aboriginal women.
"This is a call to action that this must end now," he said in a statement. "We cannot add one more name to the list of murdered or missing women. We need to see action by all parties to end violence, to respect and honour women and families, to ensure our communities are safe and secure for all."
Megan Leslie, the MP for Halifax and deputy leader of the NDP, stood in the House of Commons to call on the federal government to establish a national action plan on violence against women.
"Today, our community mourns," Leslie said, sounding emotional. "It is time for us to acknowledge this crisis and for us to act."
Status of Women Minister Kellie Leitch expressed her condolences to Saunders's family and said the government has put more money into preventing violence against women.
Const. Pierre Bourdages of Halifax police said Saunders's body was at the medical examiner's office in Saint John, N.B., for an autopsy in the coming days. He said many pieces of information led police to the location close to the highway.
"The body was not found by a bystander, she wasn't found by someone driving in the area," he said. "The information that is before us helped us narrow down the area."
At a news conference Tuesday, her boyfriend said he last saw Saunders as she was leaving his home to check on an apartment he said she was subletting to Leggette and Henneberry.
Note to readers: This is a corrected story. A previous version said the car belonging to Loretta Saunders was found Feb. 19.
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