Mollie Tibbetts, 20, was last seen in the town of Brooklyn, located 50 miles west of Iowa City, according to the Poweshiek County Emergency Management Agency.
"She might have on a FitBit, and she might have her cellphone", her boyfriend, Dalton Jack, told ABC.
She sent Jack a photo on Snapchat at 10pm that evening, and then was not heard from again - and did not turn up at work the following day.
In the days leading up to her daughter's disappearance, Calderwood said everything appeared normal - there was nothing unusual and her daughter was her normal "full-of-life" self.
"She's an incredibly responsible, intelligent person". She said that a home-to-home search that has already been conducted is expected to be repeated because many people were not home during the original canvas, likely because they were participating in the ground search.
Volunteers have been out searching for Tibbetts, but so far have found no trace of the student. "There is no such thing as a silly tip or lead".
Their efforts were aided by officials, who used a helicopter in hopes of spotting Tibbetts.
The doting aunt also described her niece as "smart and funny" and "a bit of a smart ass".
Tibbetts' mother, Laura Calderwood, still has "no idea what happened to her", the Cedar Rapids Gazette reported Monday. "She was getting ready to move into her first apartment". The University of Iowa, where Tibbetts is due to be a sophomore, releases a statement that they are monitoring the situation and offering support where needed.
Says Heaston, Tibbetts' cousin: "We want her to know that we will never stop looking for her". She's a 5-foot-3 white woman with brown hair and eyes, weighing 120 pounds.
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.
Searchers have very little information. The next day, he went to Dubuque for his work at a construction company. "So basically she's probably either in running tights & sports bra or a red short & denim shorts".
Anyone with information about her is urged to contact the Poweshiek County Sheriff's Office at 641-623-5679.
"Everything's on the table, unfortunately", Poweshiek County Sheriff Thomas Kriegel said.