One day after a man walked into an Abbotsford high school and stabbed two students, killing a 13-year-old girl, charges have been approved against a suspect.

Gabriel Brandon Klein, a 21-year-old with no fixed address, has been charged with murder and aggravated assault in connection with the attack, which early evidence suggests was committed at random.

"We do not believe the suspect has ties to the school, to the two girls, or to the Abbotsford community," Staff Sgt. Jennifer Pound of the Integrated Homicide Investigation Team said Wednesday.

Klein has been frequenting the Vancouver area since around February this year and is believed to be from Alberta originally, but police have confirmed few other details about him.

Pound asked anyone who knows the suspect or has seen him to contact police and help with their investigation.

"Until we can learn a little bit more about who this is, we're not going to have a definitive answer on what [the] motive looks like," she told reporters.

The other victim of the attack, a 14-year-old girl, remains in hospital in stable condition, and police said she is facing a lengthy physical and emotional recovery. The two students were friends.

A source speaking on behalf of her family described the teenager as a fighter who is in good spirits. Relatives asked that friends not visit her in hospital until she's more stable.

Condolences pour in for deceased

The survivor's name is protected by a court-ordered publication ban, but the deceased has been identified on social media and an online fundraiser as Letisha Reimer. Comments offering condolences to her parents paint a picture of a beloved young girl who lit up the lives of those who knew her.

"She is a true gem and we were lucky to have her be a part of our lives. Thank you for that," one well-wisher posted.

"She was beautiful – heaven has gained another angel," said another.

Many in the Fraser Valley community were left struggling to make sense of the tragedy, including the victims' fellow students at Abbotsford Senior Secondary School.

Flags were lowered to half-mast on Wednesday and there were flowers placed near the entrance to the school, which the district has said will remain closed to students for the rest of the week. Grief counsellors were made available at a church across the street for those who needed extra support.

It was particularly troubling for those who witnessed the horrifying attack.

"I feel sick to my stomach," said one student, who described watching Reimer being stabbed four times.

"I was terrified, scared," the witness said. "She was really nice. I've seen her every day. She talked to me all the time."

District addresses safety concerns

Security at B.C. schools has been under scrutiny after the attack, and Superintendent Kevin Godden assured parents that every school in the district will be exercising additional caution in the short-term by locking all but one exterior door during the day.

The district practises lockdown drills throughout the year, Godden said, but protocol reviews are still being conducted in the wake of Tuesday's attack.

"Whenever we have a critical incident, we sit down as a team and review," he said. "Some decision will be made in the not-too-distant future as to whether our protocols were successful or whether they need to be changed."

Before police arrived at the school, employees stepped in and subdued a suspect, a brave response that was lauded by both police and B.C. Premier Christy Clark.

Staff Sgt. Pound said though authorities do not encourage members of the public to intervene in dangerous situations, the staff members' actions could well have prevented additional attacks.

"It is heroic, it should be commended, and we are lucky to not have further individuals who were hurt," Pound said.

Officers were called to the school shortly after 2 p.m., and arrived within minutes to find a young man being held at the scene. Students and staff were also working together to render first aid to the victims.

The startling attacks touched a nerve across the Canada, prompting messages of condolences from many public officials on Wednesday, including Prime Minister Justin Trudeau.