Warning: this story contains distressing details.
Saskatchewan RCMP said at a news conference Thursday afternoon that they now believe Myles Sanderson did all of the killing in the mass stabbing in the province on Sept. 4, and that his brother Damien Sanderson was one of his victims.
The announcement means Myles is now believed to have killed 11 people in the James Smith Cree Nation and the nearby town of Weldon, Sask.
Details of when Damien died have not yet been released to the public.
Rhonda Blackmore, commanding officer of the Saskatchewan RCMP, said Thursday that police now believe Damien did not commit any of the homicides. However, she said Damien was involved in the initial planning for what became the Sept. 4 rampage.
"It seems that there may have been something that changed as the incidents unfolded," she said.
WATCH | RCMP say man behind mass stabbings in Saskatchewan last month killed his brother:
Blackmore said she could not go into further specifics about Damien's involvement in the planning and that more would be revealed at a pair of inquests expected to happen next year.
Blackmore also said the RCMP could not speak to the motive for the murders at this time.
"We may never have all those answers," she told reporters.
What happened on Sept. 3
Blackmore also released more information about what Damien was doing the day before the stabbings.
On Sept. 3 at approximately 4 a.m CST, Melfort RCMP received a report that Damien Sanderson had stolen a vehicle on the James Smith Cree Nation. Two officers from the detachment responded about 15 minutes later.
"On their way to the James Smith Cree Nation, as part of their investigation, the officers confirmed Damien had a warrant for his arrest for a previous assault," Blackmore said.
Blackmore said the officers looked at a photo of Damien in the RCMP database, but that the last photo on record of him was from 2014.
The caller who reported the stolen vehicle suggested police search on North Road on James Smith Cree Nation. Officers found the vehicle in the area.
Blackmore said officers then searched a home in that area and found seven people inside. They all gave names to the officers, and none said they were Damien Sanderson.
Blackmore said police have since determined Damien was one of those seven people. She said he gave the name of someone else from James Smith. She noted that his appearance was a lot different than the 2014 photo on file.
Officers found the keys for the stolen vehicle inside the home, but were unable to get any information from the occupants about how the vehicle got there, Blackmore said.
"I'd like to be clear. At no time during the first 911 report to police or any of the following conversations between Melfort RCMP officers and the caller on the morning of Sept. 3 was Myles Sanderson's name or actions or any threats of violence reported to police," Blackmore said.
Blackmore says police later confirmed that Myles Sanderson and his brother Damien had been selling drugs on Sept. 3, the day before the stabbings. She said both were also involved in three violent altercations. Blackmore said these were not reported to police at the time and it is unknown if weapons were involved.
Damien had originally been charged with first-degree murder in relation to the stabbings. Blackmore said that was based on the information they had at the time.
She said the charges against both Damien and Myles were withdrawn by the Crown following their deaths.