Authorities searching for a missing 18-year-old Berthoud woman on Friday have found a body in western Colorado and arrested an ex-boyfriend she recently broke up with.

The body, that of a young woman, was found near Collbran, in Mesa County.

Ashley Marie Doolittle was reported missing Thursday night after she didn’t return home at 7:30 p.m. as expected. When family members discovered her car near the Lon Hagler Reservoir in Larimer County, the county sheriff’s office was called just before 8 p.m. and a search launched.

Investigators initially said Doolittle might have been with her ex, 18-year-old Tanner George Flores, who was believed to be armed with a handgun. Flores was arrested near where the body was found and has been booked into the Mesa County jail pending charges.

Authorities said they were told Flores was distraught over Doolittle’s recent decision to end their year-long relationship.

Investigators have not definitively said the body is Doolittle.

Doolittle is the 2016 Boulder County Fair and Rodeo lady-in-waiting and had made several appearances on behalf of the event along with the fair’s rodeo queen. Her Facebook page is filled with pictures of her on horses, in elaborate rodeo outfits at formal dances with Flores.

There is a photograph of her prize-winning black and white Hereford calf licking her smiling face. In another picture she’s holding a puppy.

Posts on Doolittle’s site also show she was an FFA president and that she had won a $1,000 scholarship to Colorado State University.

A former middle school teacher of Doolittle’s told The Denver Post that the teen was always in a good mood and had a positive outlook on life.

Doolittle graduated from Berthoud High School on May 28, according to a Thompson School District spokesman. Flores had attended the high school before enrolling in an online education program, but he is no longer enrolled in the district.

Doolittle was enrolled at CSU as an agricultural business major, CSU said.

Photos on Flores’ and Doolittle’s Facebook pages show the two posing. One picture shows the pair together as recently as May 8.

“You are so gorgeous, I love you,” Flores commented on a picture of her posted last week.

The body was found about 8 a.m. Friday after authorities received a call that Flores’ Dodge pickup was spotted near Collbran. Mesa County deputies found the truck, then the dead young woman.

Collbran residents posted on a community Facebook page Friday morning that they saw Mesa County deputies and a SWAT vehicle swarming into their town.

“The Mesa County coroner’s office will release the identity, cause and manner of death at a later time,” said the Larimer County Sheriff’s Office, which is leading the investigation into Doolittle’s disappearance, in a news release.

Larimer County deputies are heading to Mesa County to investigate.

“We are still putting together the pieces on this case and still need information from anyone who has information that may be helpful to our investigation,” Larimer County Sheriff Justin Smith said. “We will not waiver in our commitment to Ashley, to her family or to her friends”

The Larimer County sheriff’s office said no further information would be released immediately, and a department spokesman has not returned several messages seeking comment.