Tanner Flores admitted to shooting his ex-girlfriend twice in the head, cleaning her body and driving the corpse from Larimer County to the Western Slope town of Collbran, about five hours from the spot she was killed, according to an arrest affidavit.

Flores, 18, is accused of killing Ashley Doolittle near Carter Lake, in unincorporated Larimer County. Mesa County deputies arrested him Friday after his family advised an investigator that Flores’ truck was parked in the driveway of his deceased grandfather’s home. Flores faces charges of first-degree murder and second-degree kidnapping.

Flores was upset that Doolittle had broken up with him after a relationship that had lasted more than a year, a friend of his told investigators, according to the affidavit.

The sheriff’s office began investigating June 9, when Doolittle’s mother called to say that she was missing and that she had found her daughter’s car at Lon Hagler Reservoir in Larimer County.

Investigators “learned through interviews that Tanner’s friends stated that they had never seen Tanner so depressed,” the affidavit said.

Flores’ father told investigators that his .22-caliber revolver was missing from a locked gun cabinet and that Flores knew where the key was kept, according to the affidavit.

A neighbor of the teen’s grandfather contacted authorities to report that “she could see a male who she thought to be Tanner Flores outside of the house near the white truck parked in the driveway. … She saw that the male had opened all the doors to the truck and pulled out what looked to be a bundled-up blanket from the back seat of the truck and set it on the ground.”

The woman also reported that she thought there was an arm sticking out of the bundle.

Flores is being held without bail in Mesa County. He is expected to stand trial in Larimer County, said Dan Rubinstein, Mesa County district attorney.