When an Iowa mom realized her 20-year-old daughter had disappeared, she texted her a promise, even though she knew her phone was dead: “We will find you no matter what.”

Laura Calderwood, the mother of University of Iowa student Mollie Tibbetts, immediately knew something was terribly wrong when her daughter didn’t show up for her job at a daycare on July 19.

“The night she went missing I was distraught,” she told KKCI 8. “I knew her phone was dead, but I sent her a text saying, ‘I love you. We’re looking for you.'”

Tibbetts was last seen jogging through her 1,400-person town of Brooklyn, Iowa, on July 18, but local reports say she’s believed to have made it home safely after her run, and was using her computer to do homework later in the night.

The psychology major had been staying at her boyfriend’s house, where she was dogsitting while he and his brother were out of town.

“To the best of my knowledge, I believe she did make it home from the run and was in [her boyfriend’s] home,” Calderwood said.

Waiting and worrying for the last two weeks, with no sign of Mollie, has been torture, Calderwood said.

“It’s just an emotional roller coaster.”

The distraught mom said she can’t go anywhere in Brooklyn without seeing her daughter’s face on a missing-persons poster.

“It’s a reality check every time I see one of those posters,” she said. “It’s like, ‘She’s gone!’”

Investigators have said it would be out of character for Tibbetts to disappear on her own, but they also can’t say what happened to her.

“She has so many people that love her, and that’s what I don’t understand. Who would want to hurt her or any of the members of our family?” Calderwood asked.

The reward for Tibbetts’ safe return jumped to $30,000 on Wednesday.