Mollie Tibbett's dad, boyfriend say they're "hopeful for a happy ending to this"

Wednesday will mark three weeks since Mollie Tibbetts disappeared. The 20-year-old University of Iowa student was last seen July 18 jogging around her town in Brooklyn.

Mollie's boyfriend, Dalton Jack, and her father, Rob Tibbetts, are still remaining hopeful she's still alive. They said the most important thing in their minds in the safe return of Tibbetts.

The reward for Mollie's safe return has now reached more than $300,000, and has generated more than 600 anonymous tips.

The Iowa Division of Criminal Investigation did not have any updates in the case Tuesday.

Mollie's father told TV9 people shouldn't put too much stock into places investigators have been searching. There's been a lot of speculation about the case, but the investigators' work can't always be shared to avoid compromising the case.

"A lot has been made of that, but authorities have told us that situation is just one of many," said Rob Tibbetts. "There's no number to it."

Jack said he went back to work today for the first time since his girlfriend went missing. He said he is trying to keep his mind busy, but doesn't doubt she is alive.

"If I'm not confident in that fact, I wouldn't be here," said Jack.

If you know anything that can help investigators in the Mollie Tibbetts case, call the tipline number, (800) 452-1111.