MEADOW LAKE, Sask. -- People who say their lives changed forever the day a teen took a gun and went to a high school and a home in northern Saskatchewan -- killing four and wounding seven -- want him punished as a grown man.

A hearing is to be held over two weeks in May and June to determine if the killer, who is now 18 but was 17 at the time of the shooting in the remote Dene community of La Loche, should be sentenced as a youth or an adult.

The young man, wearing a black T-shirt, sat quietly in Meadow Lake court Friday as his lawyer entered guilty pleas to first-degree murder in the deaths of two teachers at the school on Jan. 22.

He pleaded guilty to second-degree murder in the deaths of two teenage brothers at a nearby house.

He also pleaded guilty to attempted murder for wounding seven others at the school.

"I want justice to be done for me and my daughter," said Jackie Janvier, after watching the court appearance via video from the courthouse in La Loche.

She lost her only child, 21-year-old Marie Janvier, a teacher's aide who had recently started working at the school.

The mother said she's glad there won't be a trial, but that the only fit sentence for the shooter is life in prison.

The maximum youth term for first-degree murder is 10 years in custody. An adult receives an automatic life sentence and, under a new provision for multiple murders, can receive consecutive periods of parole ineligibility of up to 25 years for each victim.

"Losing my beautiful daughter -- my whole body went with her the day that happened," said Janvier.

"My life will never be the same. Never."

No agreed facts about what happened -- including a motive -- were submitted to the court.

At the time of the shooting, the teen's friends described him as the black sheep of his family and a victim of bullying at school. One person said the teen was often teased about his large ears.

Another student kept a screenshot of a chilling exchange that took place on social media just before the shooting.

"Just killed 2 ppl," said the message. "Bout to shoot ip the school."

Mounties, who responded to panicked calls from staff and students, said the shooter was inside the school for about eight minutes. The building's main doors had been blasted with holes. Some students fled; others hid in fear.

Substitute teacher Charlene Klyne said she was sitting at a desk when a student she recognized came to the window of her classroom door.

He then raised a gun and fired. She saw red.

"Everything burned like I was on fire," said the 56-year-old, who lost her sight and needed surgeries to remove pellets lodged in her upper body.

Klyne remembered the lovely teacher's aide assigned to her that day, Janvier, who ran to her side in tears. Janvier was gunned down when she went to get help, said Klyne.

She never saw the shooter bullied at school, and Klyne said she can't fathom why he pulled the trigger on her and others in the school.

"Him and I never had a disagreement. Why shoot me?" she asked.

"Marie? I don't think she ever had a disagreement with anybody."

Teacher Adam Wood, 35, of Uxbridge, Ont., was also a new teacher who didn't deserve such rage, said Klyne. Wood died of gunshot wounds in hospital.

Shortly after the shooting, officers were called to another crime scene in a nearby home where two brothers -- Drayden Fontaine, 13, and Dayne Fontaine, 17 -- were found dead.

Klyne believes the shooter had his 18th birthday within a month of the killings and, combined with the magnitude of his crime, is as close to an adult as a criminal can get.

"I hope he never gets out," she said.

Provincial court Judge Janet McIvor called the shooting serious and tragic, and ordered the sentencing be held in La Loche.

"It's very important that his hearing be held in the community where these events happened," she said.

With files from Chris Purdy