Roopesh Rajkumar died in hospital on Wednesday night.
His death comes less than a week after he allegedly killed his daughter, Riya Rajkumar, on her 11th birthday.
Rajkumar had been hospitalized with what police described as a self-inflicted gunshot wound since shortly after he was arrested.
He originally picked up his daughter around 3 p.m. on Thursday, Feb. 14 with plans of taking the young girl out for a birthday dinner.
When they didn’t return by 6:30 p.m., the girl’s mother notified police that she believed Rajkumar might have plans to hurt both the child and himself.
Just a few hours after that, police found Riya’s body at her father’s home in Brampton, Ont.
Rajkumar was arrested a short time later in Oro-Medonte, Ont., more than 100 kilometres away, and charged with first-degree murder.
Once Rajkumar was transferred into custody of local police, they discovered he was injured and took him to hospital, but police have declined to investigate the circumstances that lead to his gunshot wound.
The incident is still under investigation and officers have not released a cause of death for Riya.
The day Riya went missing, Valentine’s Day, wasn’t only her birthday, it was also her mother’s.
"She was so excited for her birthday, looking forward to having dinner later that evening," Riya’s mother, Priya Ramdin, said in a statement Tuesday. "Never did I think that my daughter would not return back to me."
Riya was laid to rest earlier in the day on Wednesday.
With files from the Canadian Press.