MEADOW LAKE, Sask. -- A child psychiatrist and a psychologist say it's not clear why a teen killed four people and injured seven in a shooting that devastated the northern Saskatchewan community of La Loche in January 2016.

Dr. Declan Quinn, who met with the teen four times, testified for the Crown as a court hearing resumed Tuesday to determine whether the teen will be sentenced as an adult or a youth.

"I'm as puzzled now as I was the first day I met him," Quinn said.

The teen pleaded guilty last fall to killing brothers Dayne and Drayden Fontaine in a home in La Loche before shooting up the high school where teacher Adam Wood and teacher's aide Marie Janvier died.

Quinn told court that the teen "did not come across as being clearly developmentally delayed or slow," although his vocabulary wasn't very good because of his poor educational progress.

"He interacted, for the most part, quite appropriately with me and seemed to be able to follow the conversation. At no time did he seem to be confused, mixed up or not understand what was going on when I was talking with him," said the doctor.

Quinn said the teen described himself as "quite unhappy and quite depressed and very anxious."

"He also expressed a terrible attitude towards school ... and he did not like school."

Quinn said he was concerned that the teen was preoccupied with school shootings in the United States, specifically in Columbine, but the youth didn't want to talk about those shootings or his own.

"I couldn't get any indication about why he wanted to do it, what led to it happening, but he seemed to have got it planned as how he was doing it and didn't want to give me details."

Court has already heard details about the shooter's murderous path from the home to the high school.

Dayne Fontaine, 17, pleaded for his life and said "I don't want to die" before he was shot 11 times, including twice in the head. Drayden, 13, was shot twice, including in the back of the head.

The shooter then posted messages online: "Just killed 2 ppl," and "Bout to shoot ip the school."

Surveillance footage captured his frightening walk through the halls, his shotgun raised, as students and staff ran in fear.

When police arrived, the shooter ran into a women's washroom where he put down his weapon and gave himself up.

Clinical psychologist Dr. Katelyn Harker testified Tuesday that the teen told her that he was thinking about shooting up the school for six months. But the teen also wouldn't tell her why.

Harker said he expressed remorse about shooting the Fontaine brothers but showed "empathy impairments" to others.

"He's also reported to me that he does care about what happened to the victims at the school, but there have been other times when he says that he doesn't, so it's hard to know exactly where he stands on that," Harker said.

Harker has met with the teen on a bi-weekly basis since September 2016.

In a report to the court, Harker wrote that the teen said he's still interested in firearms, "that he enjoys how it feels to shoot a gun ... and that shooting a gun puts him in a good mood."

"I was surprised he still viewed them so favourably," Harker testified.

Harker said she believes the teen has some cognitive limitations, that he denies personal problems and does not see a need to change, which she acknowledged could be an impediment to rehabilitation.

Crown prosecutor Lloyd Stang said after court that the motive may remain a mystery.

"I did not expect any magic moment in court where we would all of a sudden understand why things happened," Stang told reporters.

"We're getting bits and pieces of information from a variety of sources and we may never know the exact reasons behind what occurred."

There were suggestions in the shooting's aftermath that the teen had been bullied at school, but he told police that wasn't the case.

The teen, who can't be named because he was just under 18 at the time, has pleaded guilty to two counts of first-degree murder, two counts of second-degree murder and seven counts of attempted murder.

His lawyer, Aaron Fox, has said there isn't a simple explanation for what happened, but added his client does have cognitive, social and developmental issues.

Fox noted Tuesday that the teen was in Grade 10 for the third time when the shooting occurred and numerous special tests in elementary school had all indicated problems.

"The more information that can be placed in front of the judge about the youth and his background and his make up and his family and his upbringing, all of that will be helpful and relevant at the end," Fox said outside court.