Nathaniel K. Carrier has been charged with three counts of first-degree murder after his son and parents were killed in Prince Albert. The 28-year-old is also charged with attempted murder.

On Sunday afternoon, Prince Albert police were called to a home and found what has been described by the city's police chief as a horrific, incomprehensible scene.

Officers found three people dead: Denis Carrier and Sandra Henry, both 56 years old, and seven-year-old Bentlee. They found Bentlee's five-year-old sister Kendrah critically injured. She was airlifted to an Edmonton hospital and is now in stable condition, after multiple surgeries.

Police confirmed that Nathaniel is the son of the couple who was killed, and the father of the boy and girl victims. None of the charges have been proven in court.

"We're all still in a world of shock, and just can't believe that someone could be so sick and could do such a brutal crime to their family," said Billy McLennan, a cousin to Sandra who also lives in Prince Albert. "It's just something that you see in movies, that you never think would ever happen."

McLennan said he's known Denis and Sandra for decades, having graduated high school with them in 1983. He said the couple were high school sweethearts.

He'd most often see her when she was working at the grocery store.

"She always talked about her kids and her grandkids and asked about mine," he said. "She always had that sparkle in her eyes when she talked about them."

Seven-year-old Bentlee (left) was the victim of a homicide in Prince Albert, Sask., on Sunday. His sister Kendrah was transferred to hospital in Edmonton. (Submitted by Destiny Bradfield)

The crime has left friends and family members in a state of shock and disbelief, grappling with a long list of questions.

"How could it happen to someone so close to us? Why did it happen? Why were the kids — like how could someone do this to their mom and dad? How could they do this to their own son and daughter?"

McLennan said they can't seem to find the answers. He said he's been telling everyone the same message as people try to cope with this tragedy: "Squeeze your kids a little bit tighter at night."

Police reveal more detailed timeline

Police said a family member and a friend discovered the crime scene after going to check on the family's well-being on Sunday.

Insp. Craig Mushka said officers responded immediately and quickly determined there had been foul play. Nathaniel also lived at the home, but he was missing and so was the vehicle registered in his dad's name, police said.

RCMP located the missing vehicle in La Ronge, Sask., on Sunday but Nathaniel was not with it.

"Investigators located Nathaniel in Prince Albert that evening and felt confident that he was no longer a risk to public safety," Mushka said.

They determined he was "no longer a threat" and didn't arrest him until Tuesday afternoon. Mushka would not reveal where Nathaniel was from Sunday to Tuesday. Mushka said he expects that information to come out in court.

He said police are still trying to determine Nathaniel's actions in La Ronge. Police will not reveal the cause or manner of death, but said the killings likely happened on Saturday.

A police vehicle remains at the scene of a triple-homicide in Prince Albert, Sask., on March 30, 2020. (Chanss Lagaden/CBC)

Police Chief Jon Bergen previously said that additional mental health supports will be brought in for the officers who responded to the crime scene, because of the horrific nature.

Mushka said it's too early to say why this happened, but police will continue to gather evidence.

Nathaniel's first court date was Wednesday morning and the matter was adjourned to April 15. Online fundraisers have been started for the family members of the victims to help with medical, travel and funeral expenses.