(WESTMINSTER, Colo.) -- The Colorado Crime Lab is processing the backpack of missing 10-year-old Jessica Ridgeway for possible DNA evidence.
The backpack is the only trace of the missing girl since she vanished last Friday when she left to walk three blocks from her Westminster, Colo., home to meet friends for the walk to school. It was a route she took every day, but this time she never got there.
Ridgeway's backpack and water bottle were found on Sunday, six miles from where she was last seen. Police say the backpack is vital evidence in a case that has few leads.
"The bottom line is to give us ideas and evidence to who may have been in contact with it and where can we focus the search," Westminster Police Detective Trevor Materasso said.
The search for Ridgeway expanded on Monday, with more than 100 hundred people combing roadsides and rocky terrain. Meanwhile, police are checking reports that three weeks ago a suspicious man was seen approaching children.
"It's a piece but at this time we have nothing to say that is related to the disappearance of Jessica," said Materasso.
Police and FBI agents are still urgently going door-to-door in Ridgeway's neighborhood asking people to search their vehicles, yards and homes.
ABC News obtained exclusive video Tuesday morning that Ridgeway filmed herself last May playing with a video camera and the family dog.
"That's where the camera is. See?" she can be heard saying. "Right there, look. That's the camera."
An Amber Alert was issued on Oct. 5 for the 10-year-old, nearly eight hours after she disappeared. When Ridgeway didn't show up for class, school officials called her home.
Ridgeway's mother, Sarah, who works the overnight shift at a tech company, was asleep. She didn't get the message, which delayed her calling police.
Police say that Ridgeway's father, who lives out of state, is in a custody battle with her mother. Police do not believe Ridgeway is with him, but are not ruling anyone out.
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