Investigators have also canvassed neighborhoods and conducted dozens of interviews.
She was reported missing the following day when she didn't turn up for work.
The day after police in Kearney, Missouri shared information about a possible sighting of missing Iowa student Mollie Tibbetts, investigators said it was not her after all.
Investigators have said previously that they were confident on Tibbetts' digital footprint, but they did not release any information as to where that was.
However, Iowa Division of Criminal Investigation special agent Mike Krapfl confirmed Thursday that the reported sighting of Tibbetts wasn't substantiated and has been ruled out by investigators.
Donations have poured in over the past few days and the family is now offering a $172,000 reward for information that will lead authorities to her.
Calderwood said that her daughter's family and friends set up the Bring Mollie Tibbetts Home Safe Reward Fund, at First State Bank in Brooklyn.
During a news conference Thursday, Tibbetts' mother, Laura Calderwood of Brooklyn, said her family believes Mollie is alive.
The couple chatted via text messages and social media on July 18, just before Tibbetts went out for her evening run which, Jack said, was her regular routine.
"She's out there. We feel it". Her disappearance has gained national attention.
Police in Kearney, Missouri, said an employee at a truck stop reported Sunday that she saw someone resembling Tibbetts eating at a Taco Bell. Officials continue to search for her.
WQAD's fellow ABC affiliate KCRG in Cedar Rapids is reporting a heavy law-enforcement presence on a rural stretch of highway in Poweshiek County that could be related to the disappearance of Mollie Tibbetts.
"Sometimes I just feel her sitting on my shoulder", she said.