TORONTO — Five family members who were struck by a vehicle were targeted because they were Muslims, Canadian police said Monday.

Four members of the family were killed in the incident, and one remains in the hospital.

The incident occurred Sunday evening when a truck plowed into the group of pedestrians.

“This was an act of mass murder perpetuated against Muslims,” London Mayor Ed Holder said. “It was rooted in unspeakable hatred. The magnitude of such hatred can make one question who we were as a city.”

Police in London, Ontario, said the victims are a 74-year-old woman, a 46-year-old man, a 44-year-old woman and a 15-year-old girl.

A 9-year-old boy remains in the hospital in serious condition. The family requested the names not be released.

A man is under arrest and faces four counts of first-degree murder.

“We understand that this event may cause fear and anxiety in the community, particularly in the Muslim community, in any community targeted by hate."

- London Police Chief Stephen Williams

Police said suspect Nathaniel Veltman, 20, a resident of London, Ontario, did not know his victims. Police said a black pickup truck mounted a curve and struck the victims at an intersection.

“We believe the victims were targeted because of their Islamic faith,” London Police Chief Stephen Williams said.

“We understand that this event may cause fear and anxiety in the community, particularly in the Muslim community, in any community targeted by hate,” he said.

Police arrested the suspect in the parking lot of a nearby mall.