That's when investigators say Walker carjacked and assaulted Codell, then took her and the girl at knife-point to an area off Highway 401.
Officials say Codell was severely beaten, choked to unconsciousness, and left in the woods.
Walker, meanwhile, took the seven-year-old girl, broke into a house, and held the girl hostage, according to Sheriff Hubert Peterkin.
Negotiators were called in, but investigators say the suspect became increasingly hostile, forcing members of the Sheriff's Emergency Response Team to make forcible entry into the house.
There, they say, Walker used the child as a shield while holding a knife to her. They were able to get the suspect disarmed, and the child was taken to the hospital.
Deputies say this was a random incident, and that Walker does have a criminal record.
They believe Walker and Ellis had been in a domestic dispute at the time.
Walker is charged with kidnapping, assault with a deadly weapon with intent to kill, inflicting serious injury, armed robbery, and second-degree burglary. More charges are expected.