Toronto Police want a man to come forward so a six-year-old girl, the man's granddaughter, doesn't become the primary witness in a stabbing that left her father dead.

"I'm just getting a narrative from a six-year-old with regards to the fact that mom and dad were having an argument … The difficulty is that her father is deceased and her mother is now in custody," Det. Gary Giroux of the homicide squad told a Monday news conference.

On Saturday afternoon, 25-year-old Ludlow Gillespie was driving in the city's west end when the attack occurred. His car ended up on a Windemere Drive sidewalk as Gillespie fell out of the car and collapsed on the pavement. Witnesses say they could hear the six-year-old screaming.

Gillespie is the city's 17th homicide victim of 2010.

A relative at a Kipling Avenue apartment building said Gillespie had been trying to patch things up with his alleged attacker, who is his common-law spouse and the mother of his daughter.

Gillespie does have a 2008 criminal conviction for an incident of domestic violence involving his alleged attacker.

Melissa Lewis, 24, is charged with second-degree murder in connection with Gillespie's death. She was arrested at the scene.

No allegations against Lewis have been proven in a court of law.

Police allege a man in his 50s, who was also a passenger, witnessed the altercation and walked away with the girl. Another family member brought the girl to police at 11 Division.

The child is now in the custody of the Children's Aid Society.

Police are relying on the child's account of the incident, but would like to speak to the man who is described by police as being the suspect's father.

David Winn, 54, is asked to contact police immediately.

With a report from CTV Toronto's John Musselman