During a news conference Monday, Kampfer said authorities are working two angles; one being that Hailey is a missing person who is alive.
"We're optimistic, and that's our hope," Kampfer said.
The other part of the investigation is criminal. Kampfer said that portion of the investigation would mean Hailey is deceased or being held against her will.
"By talking to you, I'm letting those bad guys know that we're going to find them," said Kampfer. "We're very aggressive."
Kampfer added that multiple leads are taking investigators in different directions. He said he can't predict what law enforcement will be doing tomorrow or the next day because they're aggressively following leads that are taking them throughout the Colorado City area.
"You're going to have failure and successes, and we've had both," added Kampfer. "They (investigators) are doing a great job."
Kampfer confirmed that two girls at Colorado Middle School were interviewed Monday. Investigators believe the girls may be the pair spotted with Dunn in the hours before she went missing. The girls will continue to be interviewed in an attempt to verify that information, he said.
Authorities also added that Lamar Advertising now has more than 100 billboards up across the state featuring Hailey's image.