BARRON - As the holiday season approaches, Barron residents are holding onto hope that 13-year-old Jayme Closs will return home.

Jayme has been missing since the middle of October, when her parents, James and Denise Closs, were found shot to death in their home outside Barron city limits. Authorities ruled the deaths homicides and consider the Riverview Middle School student to be endangered.

More than six weeks later, police and residents appear to remain optimistic that they'll find Jayme alive. The Barron Area School District asked students, staff and community members to wear green Friday to "serve as a symbol of hope for the safe return of Jayme Closs."

And a Christmas tree adorned with green ribbons and Jayme's name now sits in the lobby of Barron's Justice Center.

"The hope is still out there," said Barron County Sheriff Chris Fitzgerald. "The community holds a lot of hope."

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But lingering beneath the optimism are a host of unanswered questions and frustration with a case that's confounded law enforcement.

Fitzgerald said there's no evidence suggesting drugs were involved.

Authorities aren't sure whether sex trafficking could be a factor, he said.

Based on her phone and social media accounts, Fitzgerald said, it doesn't appear Jayme has a boyfriend who might have been involved.

And though she hasn't officially been ruled out as a suspect, he said Jayme's social ability and digital footprint don't point to anything other than a "13-year-old very innocent girl."

"We just don’t see her being the mastermind behind this case or even being part of it," he said.

Fitzgerald said there are at least 25 to 30 people working on the case throughout the day, reviewing video, social media and more. Authorities were looking for two potential vehicles of interest earlier in the investigation, but Fitzgerald said they're not as "keen" on those anymore. The number of tips has tapered off to less than 25 a day, he said.

Jayme's case is difficult for law enforcement, particularly because the circumstances are so unusual, Fitzgerald said. And the "million-dollar question," he said, is whether the incident was random or targeted. Authorities still aren't sure.

"It’s very frustrating, though, to not have anything to tell people or report," he said.

The FBI tweeted a photo of Jayme's "Tree of Hope" on Wednesday, reminding the public that investigators are still looking for tips to help find Jayme. Anyone with information is asked to call 855-744-3879 or email jaymetips@co.barron.wi.us.

"Our thoughts are with Jayme's family and friends this holiday season," the FBI wrote.