Mark Arcand's nephews woke to screams Sunday morning.

Two intruders had come in through the window of their house on James Smith Cree Nation around sunrise, Arcand told Reuters on Wednesday. When one nephew, 13-year-old Dayson Burns, opened the bedroom door, they stabbed him in the neck.

Two younger boys, aged 9 and 11, cowered in the ensuing melee, which left their mother Bonnie Burns, 48, and eldest brother Gregory Burns, 28, dead in the yard outside. A woman who responded to Burns's call for help was also killed. Dayson survived.

"These two young boys woke up to screaming," Arcand, Saskatoon Tribal Council Chief, told reporters earlier on Wednesday.

The stabbing spree left 10 people dead and injured 18 others, spanning 13 sites across the two tiny communities of James Smith Cree Nation and Weldon in rural Saskatchewan.

The attacks were among the deadliest in Canada's modern history and rattled a country unaccustomed to acts of mass violence. Police said some of the victims appeared to have been targeted, while others were apparently random. (Graphic: https://tmsnrt.rs/3TIFx2F)

On Tuesday morning Burns's husband Brian posted on Facebook that he could not even return home to grab belongings: there was too much blood inside the house.

Reuters could not independently confirm this.

Police identified two brothers, Damien and Myles Sanderson, as suspects, charging the men with three counts of first-degree murder, one count of attempted murder and one count of breaking and entering in relation to the weekend attacks.

Damien was found dead Monday with injuries police said were not self-inflicted. His brother Myles went into medical distress after his arrest on Wednesday and was pronounced dead at a hospital, police said. [nL1N30E198]

Sunday's violence raised questions about violence, trauma and substance use prevention and policing in remote and indigenous communities that are frequently marginalized.

More than 90 minutes passed between the first calls to police and the first alert Royal Canadian Mounted Police sent out Sunday morning. Police did not respond to questions about the time frame on Wednesday.

CRIMINAL HISTORY

Myles Sanderson had a lengthy criminal record - convictions on 59 offences, just under half of them for failing to comply with conditions or failing to attend where required, according to parole documents reviewed by Reuters. He was also convicted of aggravated assault and assaulting a police officer, among other charges.

A warrant had been out for Myles Sanderson's arrest since May, when he failed to make required contact with his parole officer. Saskatoon Police would not say what actions had been taken to apprehend him.

Federal inmates are eligible for statutory release after serving two-thirds of their sentence. It is a presumptive release by law, although it can be revoked for violations or if someone is believed to present an undue risk to the public. In 2021-22, only 0.8% of people on statutory release had it revoked due to violent reoffending, according to data from the Parole Board of Canada.

Canada's Public Safety Minister Marco Mendicino said this week the Parole Board is reviewing the decision to release Sanderson - a review Mendicino's office said the board initiated.

The parole board released Myles Sanderson in February over the objections of his community parole supervisor, deciding that he would not "present an undue risk to society if released", according to the parole documents.

His statutory release had been suspended last fall because he lied about living with his ex-spouse, the documents showed.

In April 2018, Sanderson stabbed two people with a fork and then beat one man until he lost consciousness in a ditch, his parole documents read.

Sanderson's childhood involved physical abuse, domestic violence and instability, the documents read.

He started drinking alcohol and smoking marijuana at age 12, cocaine at age 14 and crystal methamphetamine for a three-month period in his late 20s. Substance use made him "lose (his) mind," the parole documents say, adding he can be "easily angered when drunk."