Investigators have found evidence that a missing University of Iowa student was doing homework on her laptop the night she went missing, according to the woman's brother.

Mollie Tibbets, 20, went missing on July 18 when she went jogging near Brooklyn, Iowa. TIbbets' brother, Jake, says investigators found that evidence that she was on her laptop that evening.

The older brother of 20-year-old Mollie Tibbetts says investigators told him evidence shows she was doing homework on her computer last Wednesday evening.

Tibbets was reportedly dog-sitting for her boyfriend, Jack Dalton, at the time of her disappearance. It is unclear if she returned after her jog, but the new details, family members say it is possible she did.

Investigators previously executed a search warrant for Tibbits' Fitbit and social media accounts. A spokesperson for the Iowa Department of Criminal Investigations said Tibbets' case may be the first time Fitbit data has been used in an investigation in the state.