Ontario police have arrested a man in the death of his seven-year-old stepson and the stabbing of a bank employee, following a nationwide warrant.

According to a police spokesperson, 43-year-old Justin Kuijer, of St. Catharines, Ont., was arrested Tuesday in Kenora, Ont., a small city near the Manitoba border more than 1,900 kilometres northwest of where the alleged crimes occurred last Friday.

Kuijer faces charges of second-degree murder in the death of his stepson Nathan Dumas and attempted murder in connection with the attack on the bank employee.

The police manhunt began on Friday when a man entered a Royal Bank of Canada branch in St. Catharines and stabbed a female employee. The woman was rushed to hospital, where she is believed to be in stable condition. As police responded to the stabbing, officers were also called to a home in the city, for a seven-year-old boy who was in medical distress.

Police allege Kuijer attacked Nathan on Friday morning, causing undisclosed injuries. Nathan died in hospital on Saturday.

On Monday afternoon, Niagara Regional Police confirmed that they had received judicial authorization for a Canada-wide arrest warrant for Kuijer.

Police say Kuijer is the stepfather of the young boy and had a professional relationship with the bank employee who was stabbed.

In an obituary, Nathan’s family described the child as a caring, considerate boy who never missed an opportunity to come to the defence of a friend.

“Our family will forever cherish the fond memories he brought to us,” the obituary read. “Nathan was a truly kind, loving boy with a big heart, full of compassion for everyone and everything.”

The obituary went on to say that there are “no words to express the unbearable heartbreak we feel in his loss."

On Tuesday, school officials told CTV Toronto that students at Harriett Tubman Elementary School, where Nathan attended Grade 2, were writing down their favourite memories of Nathan.

Their tributes will be placed in a memory box that will be presented to the family.

A memorial with flowers and teddy bears continued to grow outside Nathan’s family home on Tuesday. A funeral will be held on Friday in St. Catharines.

With files from CTV Toronto’s John Musselman and The Canadian Press