(CBS/AP) WAUKESHA COUNTY, Wis. - Kathryn Stalbaum, a 15-year-old Wisconsin girl, went missing Tuesday morning while riding her bike to school, reports CBS affiliate WDJT.
Authorities have since found her bike, but there has been no sign of the teen.
Authorities in Waukesha County say Stalbaum had texted a friend early Tuesday saying she had missed her bus and would be riding her bike to Kettle Moraine High School, 2 miles away from her home.
"We don't know what happened to Kathryn," said Waukesha County Sheriff's Department Inspector Eric Severson. "I don't know if she's left voluntarily. I don't know if she's left against her will. I don't know."
According to the station, the teen's bike was found across the street from Waukesha Memorial Hospital.
Officials have searched the area around Stalbaum's school, her home and the route she may have taken to school Tuesday. Dive teams also reportedly searched ponds in the area.
Stalbaum is described as being 5-foot-7 and 120 pounds with long brown hair, blue eyes and braces. She was last seen wearing jeans, a sweatshirt and bright pink Nike tennis shoes, according to WDJT.
CrimeStoppers is offering a $1,000 reward in the case.
Authorities are asking anyone who knows anything about Stalbaum's whereabouts to call the Waukesha County Sheriff's Office at 262-446-5090.