On Wednesday afternoon, authorities changed course more definitively, saying they believe Jessica was kidnapped by an "unknown suspect."
Adding to the mystery was a reported sighting more than 2,000 miles away in Maine of a car with Colorado license plates — one of hundreds of leads being investigating from at least five states.
Amid it all, there's still no sign of Jessica, the fifth-grader with blond hair and glasses who loves math and gym class.
Police in the Denver suburb of Westminster repeatedly have urged the public to study the details of her face in a photo — a small, gap-toothed grin, a slight bruise on her nose — and a short home video, in hopes they may have seen something or come across the girl. They've thanked thousands of Coloradans and others for helping with a search they have insisted is focused on the area surrounding Jessica's home.
For days, police only hinted at the possibility of a kidnapping. But at a news conference Wednesday, Westminster police spokesman Trevor Materasso said authorities believe the girl was abducted by an unknown person.
He also said the investigation's focus is not the girl's parents, who are cooperating. Jessica's mother lives Colorado, and her father lives in Missouri.
"We're confident they are not involved in Jessica's disappearance," Materasso said.
Just one day earlier, investigators organized, at police headquarters, a TV interview with Jessica's parents, Sarah Ridgeway of Westminster and Jeremiah Bryant of Independence, Mo. While it was being conducted, an FBI evidence team went into Jessica's home one more time for unspecified reasons.
The only real clue police have revealed is the discovery over the weekend of a backpack and water bottle that Jessica had with her when she disappeared. The items were found in the town of Superior, some six miles from her home. Police won't discuss what was found in the bag or testing results on it.
The search for Jessica went national, thanks in part to social media and a Facebook page set up to help find the girl.
"Do your good deed of the day and retweet Jessica's photo," hundreds of Tweets urged Wednesday.
In Dexter, Maine, 2,000 miles east, a woman reported seeing a girl who looked like Jessica on Sunday, in a blue Buick station wagon with Colorado plates. Authorities issued a statewide alert for officers to stop any blue Buick station wagons with Colorado plates, Dexter police Sgt. Alan Grinnell said.
Citizens also have passed on tips from Maryland, Texas and Nevada, Materasso said.
Also of interest: the abduction and assault of an 11-year-old girl Monday in Cody, Wyo., some 500 miles north.
In that case, a man lured the girl into a sport utility vehicle, saying he needed help finding his puppy. The girl was released four hours later and was discovered by hunters. Police there are looking for a white man, between 55 and 60 years old, with short, strawberry-blond or white hair and a neatly trimmed mustache.
Westminster police spokeswoman Karlyn Tilley noted there is "no specific connection" between Jessica's disappearance and the Wyoming case.
"It's just like everything else they're looking at," Tilley said Wednesday. "They just don't want to leave any stone unturned."
Police in neighboring Arvada earlier backed off a possible link between Jessica's disappearance and reports of a suspected predator approaching two children in the weeks before. Police said there was no evidence connecting the incidents. A body has been found near an open space area in Arvada, but Materasso said that so far, police haven't connected it to Jessica's disappearance.
On Wednesday, about 25 deputies arrived by bus and fanned out across Jessica's neighborhood, scouring bushes and front yards.
Divers again searched ponds in what Materasso described as a "precautionary measure." Police have isolated trash from Jessica's neighborhood at a landfill — but will search there only if the investigation points them in that direction, Materasso said.
Critical was an initial delay in reporting Jessica missing. Many child abduction cases or Amber Alerts are resolved within hours of a report, as was the case in the Wyoming abduction Monday.
Sarah Ridgeway said her daughter woke up at 7:45 a.m. Friday as usual and ate a granola bar before leaving to meet friends at a park about a block away for their walk to Witt Elementary School. Police say Sarah Ridgeway, a night-shift worker, was asleep and missed a call from school reporting Jessica absent. She got the message when she woke at about 4 p.m., eight hours after she said her daughter left the house.
Sarah Ridgeway checked the park, Jessica's friends and the school before calling police. Jessica never even met her friends that morning.
Police also searched Bryant's home in Missouri, where Bryant was at work on Friday, before he traveled to Colorado to be with Jessica's family.
The protracted search has concerned students and parents throughout the area. Jefferson County's school district urged parents of students to update their contact information as a first step "in determining any changes in our attendance practices."
"Jessica's disappearance has understandably created concern for the safety of all students," the district said in an email. "Please join us in helping to keep your children safe.