WOODLAND PARK, Colo. — For the first time since a judge ordered authorities to not discuss the case, Woodland Park Police Chief Miles De Young is speaking publicly about the killing of Kelsey Berreth.

Berreth’s fiance Patrick Frazee was convicted Monday of murdering Berreth and sentenced to life in prison without parole.

The Fourth Judicial District Attorney said De Young’s strategies early in the investigation were crucial in helping solve the case.

In an exclusive interview with FOX31 and Channel 2, De Young spoke about the moment he knew he would have to call for help from outside agencies to catch Berreth’s killer.

“It was some of the initial inconsistencies about where Kelsey may have gone and Cheryl’s (Kelsey’s mother) persistence when she said something wasn’t right. And that made us dig a little bit deeper. And then we realized this looked like more than just a missing person’s case,” De Young said.

He says investigators detected discrepancies about Berreth’s disappearance and knew his team a much more serious case on their hands.

De Young says the case had a tremendous emotional impact on his officers.

Moreover, he says the most difficult part of the case was ensuring Berreth’s 1-year-old daughter was safe.

“The hardest part about this case was Kaylee (Kelsey’s daughter) and knowing that she was with Patrick (Frazee). And knowing the testimony that Krystal (Lee) had given us about what had occurred and that Kaylee was present when her mother died. And hoping that nothing bad happened to Kaylee while I was trying to get her paperwork in order. That was my biggest fear,” De Young said.