Alek Minassian, the suspect in Monday's van attack in Toronto, joined the Canadian Forces last August and got 16 days into his 13-week basic training before he asked to leave, according to a statement from the Department of National Defence.

But even in that short time — September to late October — Minassian made an impression at the military's leadership and recruit school in Saint-Jean-sur-Richelieu, Que.

"He wasn't very good at taking direction," said fellow recruit Andrew Summerfield. "There was a lot of disciplinary action put towards Alek because he wouldn't understand something and they'd want him to do it, and then he wouldn't do it right."

Summerfield told CBC News that Minassian struggled to pass morning inspections that involved folding his clothes properly and making his bed to military standards.

He said it appeared Minassian "had some sort of condition," but he never shared what it was with Summerfield and other members of their platoon.

Minassian attended the military's leadership and recruit school in Saint-Jean-sur-Richelieu, Que. (Jaela Bernstien/CBC)

"I spent a decent amount of time with him one on one trying to get him to be able to understand stuff, but it just seemed like he didn't have the capacity," said Summerfield, who has since left the military. "You could tell he was very socially inept."

A senior Canadian Forces official told CBC News about similar issues with Minassian, including dress, deportment and group interactions in a military setting.

You could tell he was very socially inept. - Andrew Summerfield, fellow recruit

But nothing during Minassian's time in training would have pointed to the potential of his involvement in Monday's rampage, according to the official who spoke on condition of anonymity.

"He wasn't adapting to the military lifestyle," the official said. "There were no red flags and nothing that would point to anything like this."

He complained about his dislike of military discipline and was quickly judged an average or below-average recruit.

He had had no weapons training by the time he was released, the official said.

Toronto police arrested Minassian Monday after the driver of a rental van mowed down pedestrians along a busy stretch of Yonge Street, north of downtown.

This morning, Minassian was charged with 10 counts of first-degree murder and 13 counts of attempted murder.

Minassian, who is charged with 10 counts of first-degree murder and 13 counts of attempted murder, made a brief court appearance in Toronto Tuesday morning. (Pam Davies/CBC)

"I'm in such shock," said Summerfield. "It doesn't seem like something Minassian would have been capable of by any means … he just seemed like a quiet dude that went to school for computers and would end up programming for the rest of his life."

Summerfield wasn't surprised when his fellow recruit asked to leave basic training, but the fact that Minassian was recruited in the first place gives him pause.

"Personally I wouldn't want to go into an armed conflict with someone like Minassian who can't understand instructions," said Summerfield. "It makes me wonder how effective recruitment really is."