A man and a woman were shot and killed Monday at an office next to a daycare centre and a school in north Toronto, and a man suspected as the attacker has also died, authorities said.

The shooting caused both a daycare facility and a Catholic boys elementary school to be put on lockdown, with parents rushing to pick up their children.

Detective Sergeant Al Bartlett said the man and woman who were killed ran a business together that involved financial transactions.

“At this time we believe the altercation that occurred is related to that business,” Bartlett said.

“The person we believe to be responsible is among the dead,” he said.

He kept the identities of the victims and the attacker secret, saying authorities would have to inform their families first.

Bartlett declined to comment on whether the suspect killed himself or died another way, saying it was still under investigation.

Bartlett said no children were injured. He said there was no access inside the building between the daycare center and the business.

Shahrukh Biniaz, a graphic designer and photographer whose studio is in the building where the shooting occurred, said he heard a loud explosion and heard people arguing in the reception area.

“I didn’t know what it was, I thought maybe it was a circuit breaker or something because it was making a really loud noise,” he said.

“I came out of my office and heard some arguing in reception … I went back to my desk and sat down, and I heard a second blast two minutes later.”

He said he came out of his office again, heard sounds of fighting and then left the building through the back door.

“I called 911. The police came pretty fast,” he said, adding that he then heard another gunshot.

Relieved parents were seen hugging their children tightly after being reunited just outside the police tape at the St George Mini School daycare.

An observer told the crowd of parents gathered there that everyone inside was safe.