Police in southwestern Ontario have ended a "thorough" ground search for an eight-year-old Woodstock girl, but continue to investigate her disappearance as a missing persons case.

Victoria (Tori) Stafford was last seen leaving her school on Wednesday afternoon. (Photo provided by Woodstock police)Meanwhile, investigators are still not treating Victoria Stafford's disappearance last Wednesday as an abduction because video surveillance showed the Grade 3 student leaving her school "willingly" with an unidentified woman, police Const. Laurie-Anne Maitland said.

"An abduction says that it’s taken by force. We have her willingly walking away," Maitland told reporters Monday.

Police have received more than 300 tips from the public in the case and are examining a "variety of items” found in the ground search, but none of the items was related to what the girl was wearing at the time of her disappearance, Maitland said.

There is a "feeling" among investigators that the girl is alive and the ground search could be restarted if new information becomes available, she said.

"When we’re actively doing a grid search, we’re not looking for a necessarily happy, healthy eight-year-old," she said.

"We haven't found anything to indicate or support foul play, and that's what keeps me hopeful."

Surveillance video released over the weekend showed the girl, known to her friends as Tori, walking with an unidentified woman as she left school Wednesday afternoon in the city of 35,000 east of London.

Police issued Monday afternoon a new, less grainy version of the video, giving what investigators hoped was a clearer view of the unidentified woman last seen with missing eight-year-old Victoria Stafford. (CBC)Police issued a new version of the video Monday afternoon, making it clear they believe it may be a key to the case. Their technicians removed some of the graininess, giving what investigators hoped was a clearer view of the woman last seen with Tori.

The woman in the video is described by police as between 19 and 25 years old, between 120 and 125 pounds, with long, straight black hair in a ponytail. She was wearing a white coat and black jeans.

Behavioural specialists from the Ontario Provincial Police have been called in to develop a profile of someone who might be involved in the girl's disappearance.

Family has 'no answers'

On Sunday night, about 1,000 people joined the girl's relatives for a candlelight vigil in Woodstock.

Stafford's parents, Tara McDonald and Rodney Stafford, separated last December. The father, who described the relationship as "an ongoing struggle," said he doesn't believe any of Victoria's relatives are behind her disappearance.

"I have no answers," the missing girl's mother said at the vigil. "Nobody can even begin to imagine what our family is going through."

Surrounded by his family at the vigil, Rodney Stafford thanked the hundreds of people who have helped search for his daughter.

"To me it is a dream, and I wish someone would slap me and wake me up, and preferably it be Tori," her father said.

Anyone with information can call police at (519) 537-2323 or contact Crime Stoppers anonymously at 1-800-222-TIPS.

With files from The Canadian Press