After a days-long manhunt, police in northwestern Ontario have arrested a man accused of killing his seven-year-old stepson in St. Catharines late last week.

Jeff McGuire, chief of Niagara Regional Police Service, confirmed the arrest, saying Ontario Provincial Police took Justin Kuijer into custody in Kenora, Ont., not far from the Manitoba border.

"Uniform officers from the Kenora Detachment of the OPP responded to a 911 call from a member of the public," a news release from the Niagara police force said.

They found Kuijer sitting inside the 2009 Pontiac Montana van that police said he was driving when he fled St. Catharines.

Kuijer was arrested "without incident," police said. He was alone when he was arrested, and "will be returned to the Niagara Region in the days to come."

Kenora is about 200 km east of Winnipeg.

Police issued the Canada-wide warrant for Kuijer on Monday, describing the 43-year-old as armed and dangerous.

Niagara police allege that Kuijer attacked his stepson, Nathan Dumas, on Friday morning. The child, aged 7, was found in medical distress at his home on Queenston Street in St. Catharines.

He died Saturday in hospital.

The family has planned a funeral for this Friday, one week before what would have been the boy's eighth birthday.

Kuijer was also wanted in connection with the stabbing of an employee at a local RBC branch shortly after Dumas was attacked. Police have only said that the woman and Kuijer are "known to each other professionally."

Neighbour Tammy Vanblaricum, who lives next door to the family, said Tuesday she is "so happy" that Kuijer was caught.

"It's a big relief for everybody, the family," she said Tuesday evening. "Rest in peace, little one."

Police in Niagara plan to update the media on the case Wednesday at 12 p.m. ET.