ST. CATHARINES, Ont. - Police have issued a Canada-wide warrant for a man accused of killing his seven-year-old stepson.

Niagara regional police Const. Phil Gavin says 43-year-old Justin Kuijer of St. Catharines, Ont., is wanted on charges of second-degree murder and attempted murder.

Police had earlier said they would be seeking a warrant for first-degree murder but gave no explanation for the change in the charge.

Kuijer is accused in the death of Nathan Dumas, who was found by a family member suffering undisclosed injuries on Friday morning. He was rushed to hospital where he died the next day.

The attempted murder charge stems from what Gavin describes as a targeted attack on a woman working at a nearby RBC branch.

Police say Kuijer is armed and dangerous and are urging the public to contact them if they have any information on his whereabouts.

Kuijer was last seen wearing an orange hoodie under a brown leather coat, dark pants, a black toque, and boots, police said. There is a pink floral decal on the back window of the dark grey van he was driving that references missing person Ashley Simpson and "Missing Women of Canada."

The suspect van's licence number was BYTE392, police said.