It has been five days since 20-year-old University of Iowa student Mollie Tibbetts vanished without a trace after heading out for a run in Brooklyn, Iowa, and local authorities tell PEOPLE they are investigating multiple possible answers to the mystery.
“We still haven’t found her and to be honest with you, we don’t know what happened to her,” says Poweshiek County Sheriff Thomas Kriegel. “We don’t know if she was abducted or if she’s just gone off for a couple of days to relax with friends. We don’t know.”
According to the sheriff’s office, the last reported sighting of Tibbetts was Wednesday evening. She was spotted jogging while wearing gym shorts, a black sports bra and running shoes.
Tibbetts, a California native who lives in Brooklyn, was dog-sitting around the time of her disappearance.
Detectives are still trying to determine for certain if she “disappeared while jogging or if she left from the house afterwards,” Kriegel tells PEOPLE.
“At this point,” he adds, “everything is being considered — we are looking at everything and everybody.”
He explains: “We have been working to eliminate areas where she could be at and checking people we might suspect, but who are not suspects yet … we’re just seeing where they were and checking their whereabouts.”
Tibbetts was reported missing on Thursday by relatives, Kriegel says.
“We know that Mollie knows how much we love her and how important she is to her entire family,” cousin Emily Heaston tells PEOPLE.
“We know Mollie wants to be home,” says Heaston, 35.
A massive ground search involving more than 200 people broken up into 37 teams was conducted Friday, encompassing the farmlands and fields within a five-mile radius of Brooklyn, with helicopters hovering above, according to authorities.
Kayakers were also directed to sweep two small rivers for clues, Kriegel says, and other area bodies of water were searched.
Investigators have also been working to review Tibbetts’ digital footprint, including what is on her laptop and her social media activity, according to her family.
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Calls to Tibbetts are going directly to voicemail, Kriegel confirms, meaning her phone was turned off or no longer works.
“We hope she is with friends,” he says. “I’m hoping she was stressed out and needed some time away from everybody.”
Still, the sheriff says his department is “preparing for the worst” and notes investigators have been handling the disappearance with the same vigilance they would ascribe to a known criminal case.
Kriegel says that on Monday morning, law enforcement gathered to review the entire case, go over everything they have done until now and map out “the rest of the week.”
“We will update that plan as needed until there is some sort of resolution here,” he says.
Says Heaston, Tibbetts’ cousin: “We want her to know that we will never stop looking for her.”
Tibbetts is described as 5-foot-3-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.
• With reporting by ADAM CARLSON