Twenty-year-old Mollie Tibbetts was reportedly dog-sitting in Brooklyn, Iowa, on Wednesday night when she headed out for a jog dressed in typical workout gear.

She has not been seen since, according to authorities — leaving loved ones “worried sick and desperate to get Mollie home,” one relative said, as investigators continue to scour the area for clues to her whereabouts.

“There is no such thing as a silly tip or lead,” Emily Heaston, who is Tibbetts’ cousin, according to the Des Moines Register, wrote on a Facebook group set up in support of the search effort.

Tibbetts, a student at the University of Iowa, was staying with her boyfriend at the house where she was dog-sitting when she decided to go for a run, ABC News reports.

She was last seen in gym shorts, a black sports bra and running shoes while jogging near Brooklyn, according to a brief news release from the Poweshiek County Sheriff’s Office, which is leading the investigation. (A dispatcher who answered at the sheriff’s office on Sunday said they were unable to provide more information, referring a reporter to the news release.)

“She might have a FitBit on and she might have her cellphone, but obviously we’ve tried just calling her but it’s either off or dead so it would go straight to voicemail,” her boyfriend, Dalton Jack, told ABC.

Among the last contact the two shared, Jack said, was a typical Snapchat photo she sent him that Wednesday night.

The surrounding miles of farmland, fields and roads have since been canvassed by hundreds of volunteers, according to ABC News and Tibbetts’ family’s posts on the Facebook search group.

In a Facebook post on Friday, the University of Iowa said its “thoughts are with Mollie Tibbetts’ family and friends” and that school officials were “monitoring the situation and will offer support as needed.”

According to Tibbetts’ Facebook profile, she is studying psychology and has interned at the Grinnell Regional Medical Center. She lives in Brooklyn and is originally from Oakland, California.

Her aunt Kim Calderwood, who called her “very responsible and conscientious,” told local TV station WOI that their family was not giving up: “We miss you, we’re looking for you and we will never stop.”

Tibbetts is described as 5-foot-2-inches tall, weighing about 120 lbs., with long brown hair and brown eyes.

Anyone with information about her is urged to contact the Poweshiek County Sheriff’s Office at 641-623-5679.