The Ontario Provincial Police on Saturday launched what they said would be an intensified search in Woodstock, Ont., for missing eight-year-old Victoria (Tori) Stafford.

Victoria Stafford, shown in a family photo from July 2008, has been missing since she left her school in Woodstock, Ont., on April 8. (Canadian Press)

Under the direction of Det.-Insp. William Renton, officers were scouring all local waterways, including a pond, about one kilometre from the school where the girl was last seen on April 8.

The OPP's underwater search and recovery unit, working at Southside Park, planned to use sonar equipment to take a reading of the pond's bottom.

The equipment can detect objects 20 metres in either direction, scanning the area in matter of hours. The same job would take divers a couple of days, police told CBC News.

Police will also be re-examining older information and tips, and detectives will be canvassing homes and residents in the hope of uncovering some new leads.

Officers were once more going door to door, talking to people — in some cases for the fourth or fifth time — hoping to jog their memories and to touch base with people who were away for the Easter long weekend, when the search was in its early stage.

Police say the renewed investigation could last seven days or longer and there will be "significant police activity" in the local area.

On Saturday afternoon, people from the city of approximately 35,000 planned a "Walk for Tori," starting at the College Avenue Secondary School.

The most significant lead police have publicly talked about is footage from a surveillance camera mounted at the high school, capturing movements from the nearby Oliver Stephens Public School. The video shows a woman with long brown hair and a white coat walking with the missing Grade 3 student.

No one has come forward to identify the woman, and her face is not clearly visible in the grainy footage.

The case was upgraded Friday to an abduction from a missing persons case. The change in status was announced by Renton, who has stepped in to take the lead role in the investigation.

"We have pretty substantial direction in that regard,'' Renton said when asked about a possible identity for the woman in the video, but added "to go public with any sort of comment would be a hindrance.''

Tori's mother, Tara McDonald, has said she's convinced the woman is a stranger to her daughter and family.