The search for missing Iowa college student Mollie Tibbetts is ongoing, officials said at a Monday press conference, as they urged the public to provide tips and to help identify anyone who may have exhibited unusual behavior around the time of her July 18 disappearance.

“We are considering all potential scenarios,” Mitch Mortvedt, the assistant director of the Iowa Division of Criminal Investigation, said at the press conference. “It is possible to Mollie came into contact with someone who caused her harm.”

Mortvedt asked for help in identifying anyone who may have exhibited unusual behavior around the time Tibbetts vanished.

"Individuals who commit violent crimes often display behavior that is recognized by those with whom they live, work, attend school or are in otherwise close relationships with," he said.

“Please contact us if you have noticed changes,” he continued. He cited changes in “normal routine,” a “vehicle unexpectedly taken to a repair shop” or sold, changes in physical appearance, displays of anxiety, nervousness or irritability, unexplained injuries or changes in consumption of alcohol or drugs, or “interest in the status of the investigation.”

Tibbetts' father has suggested she might have been abducted from her boyfriend Dalton Jack's home in Brooklyn, Iowa. The 20-year-old Tibbetts was seen jogging July 18 and her family reported her missing the next day.

Jack's brother, Blake, told Fox News there were no signs of struggle at the home, adding that Tibbetts is "small, but she would have done something" if she had been attacked.

Despite the one-month mark of her disappearance approaching this weekend, officials remained hopeful on Monday, announcing the establishment of a website, findingmollie.iowa.gov, that lists information and methods for submitting tips.

“Our message is to continue to call in leads,” Rick Rahn, the special agent in charge with the Iowa Division of Criminal Investigation, said at the press conference. “We’re looking at all options and all possibilities and we will continue to do that until we are able to bring back Mollie.”

“We haven’t lost hope,” he said. “We continue to strive to bring her back safely.”

The Associated Press contributed to this report.