Police released latest additional details about the disappearance of 13-year-old Jayme Closs, who went missing following the murders of both of her parents in their Wisconsin home.

It has been nearly two months since Jayme was last seen and authorities are tirelessly working to locate the teen.

Authorities recently shared chilling new information about the missing girl's case, including how they are focusing on surveillance footage within 60 miles of the Closs' home.

"This case remains the #1 priority in Barron Co and across the nation," the department said in a news release shared on Facebook. "We continue to follow up on leads, expand and view our recovered video from the area and explore all digital evidence."

Barron County Sheriff Chris Fitzgerald told the Daily Mail that whoever murdered Jayme's parents left no evidence behind. There was nothing out of place, he said.

"The house wasn't disturbed at all from what we were able to tell. That's part of the confusing part of this case," Fitzgerald explained. "It doesn't appear that anything was taken, it doesn't appear that Jayme packed up any clothing."

The intruder was only in the Closs' home for four minutes and left nothing but bullet casings behind.

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"That's the frustrating part of it," the sheriff said. "We've had four different lab teams look at the scene before we released it. We were very strategic. When we discovered it was a major crime we sealed it off immediately. But if I'm in your house for minutes and I only step five feet inside your home I'm probably not going to leave a big footprint."

Fitzgerald said any information about the gun used in the crime is being withheld during the investigation.

The #FBI has posted information about missing girl, Jayme Closs, on digital billboards across the nation. Please keep your eyes out for these boards and contact the FBI if you have any information on her whereabouts: https://t.co/s0fHKjY3hc pic.twitter.com/PCRpyqZ60S — FBI Most Wanted (@FBIMostWanted) October 18, 2018

"Only the killer is going to know that and that's information we have to hold close to the case so that when we catch this person we can convict them. We are looking for that gun," he said. "We are looking for a firearm."

Detective Chris Braman of the Winnebago County Sheriff’s Department told USA TODAY NETWORK-Wisconsin that police are examining any and all surveillance footage they can in an effort to spot a suspect.

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“It’s one of the first things we do on a major case; we seek out surveillance on cases,” he said. “People have a myriad of video surveillance devices, (including) doorbell video of vehicles passing by. It’s a different way of canvassing than the old days. It’s a new age.”

Authorities responded to a 911 call on Oct. 15, where they found James, 56, and Denise Closs, 46, shot dead in their Barron, Wisconsin, home. Their daughter Jayme was nowhere to be found and is still missing.

A Christmas tree in a Wisconsin county building has been dedicated to Jayme Closs, 13, who went missing in October. Her name is spelled out in big, glittery letters, and the green color of decorations symbolizes raising awareness about missing children. https://t.co/fmlaFWUArI pic.twitter.com/yEZhbGHXCT — CNN (@CNN) December 5, 2018

Fitzgerald told USA TODAY NETWORK-Wisconsin that surveillance footage in the surrounding areas could be key to finding Jayme.

“The video will help us solve the case,” he said. “We don’t see Jayme on any of the videos. But once we arrest a suspect, it will help us convict (the person responsible).”

When a suspect is taken into custody, authorities can re-examine the footage, searching for the individual to determine what he/she has been up to and where he/she has been.

While no suspect has been identified in the case, authorities are hopeful they will find something that leads to Jayme's location.

"While 30 days has past, there is still hope in this department on this case and the community support and prayers that we have been given continues to fuel our drive and determination to bring Jayme home," the sheriff's department said on Facebook. "Thank you all for your support and prayers and again there is a tip out there that will solve this case and bring Jayme home."

Anyone with information that might lead Jayme's location is urged to call 911 or the 24-hour tip line at 855-744-3879. Sign Up for the YourTango Newsletter Let's make this a regular thing!

Sarah Gangraw writes about all things news, entertainment and crime. You can follow her on Instagram and Twitter.