 (CNN) Volunteers and law enforcement combed the side of a highway on Thursday looking for evidence in the disappearance of a missing Wisconsin teenager whose parents were found dead in their home this week. James and Denise Closs were discovered slain in their home just outside of Barron, about 90 miles northeast of Minneapolis, after cops responded to a 911 call around 1 am. Call the tip line 1-855-744-3879.#FindJayme pic.twitter.com/rNELlQKJb6 — FBI Milwaukee (@FBIMilwaukee) October 17, 2018 
 
 An Amber Alert was issued Monday for Jayme and several law enforcement agencies have joined the search. USA TODAY 
 
 Jayme Closs (Photo: Barron County Sheriff's Department) 
 
 BARRON, Wis. - A missing Wisconsin teenager was still at home when her parents were shot to death this week, the Barron County sheriff said Wednesday. More: What we know about the disappearance of Jayme Closs 
 
 Fitzgerald on Wednesday said that information from the phone call and from inside the home led investigators to conclude that Jayme Closs was home at the time her parents were killed. On Tuesday, reports surfaced that Jayme may have been spotted at a Miami gas station in a black Ford Explorer with Wisconsin tags, in the company of two “well dressed, bearded men.” But at a press conference later that afternoon, Fitzgerald said the Florida sighting didn’t appear to be a “credible tip.” 
 
 “We have followed up on that tip. Both James and Denise Closs were long-time employees of the Jennie-O Turkey Store in Barron, Jennie-O's parent company Hormel said.
– The parents of a missing 13-year-old western Wisconsin girl were shot to death, and Jayme Closs was apparently home at the time, the sheriff says. Barron County Sheriff Chris Fitzgerald said Wednesday that the deaths of James and Denise Closs early Monday have been ruled homicides, USA Today reports. He said their daughter, who is not a suspect in the killing of her parents, is in danger, but he has a "100% expectation that she's alive." He said the bodies were found after a 911 call from the home in the small city of Barron in which nobody spoke directly to the dispatcher, CNN reports. He said investigators don't know whether the attack was random or targeted. Fitzgerald said a disturbance could be heard in the background during the 911 call—but there was nobody at the scene and no vehicles to be found when emergency responders arrived four minutes later. The sheriff urged residents to come forward with any information they had on possible suspects, including people with "behavioral changes" like missing work or suddenly leaving town, the Daily Beast reports. Every second counts in this case," he said. "When a child like Jayme is missing, we ask you to observe this behavior and report it to us." Jayme, who was last seen with her mother at a family gathering Sunday, is described as 5 feet tall and 100 pounds, with strawberry-blond hair and green eyes. Read more on the case here.