By Kelly Werthmann

LARIMER COUNTY, Colo. (CBS4) – A Berthoud teenager accused of killing his former girlfriend has admitted to investigators that he shot the 18-year-old in Larimer County before driving her body to Mesa County.

According to an arrest affidavit, Tanner Flores, 18, told Mesa County investigators he shot Ashley Doolittle twice in the head near Carter Lake “because he is angry with her.” He then drove to his late grandfather’s ranch in Collbran where he said he “cleans her up before returning her to the truck.”

Flores was arrested for first-degree murder and second-degree kidnapping Friday and is now being held at the Mesa County Jail.

Doolittle was reported missing from Berthoud by her mom late Thursday when the teen hadn’t returned home. Her mother said she found her daughter’s car unoccupied at Lon Hagler Reservoir in Loveland. She also told authorities her daughter had recently broken up with Flores.

Larimer County investigators spoke to friends of Flores who said they had never seen him so “depressed” over the breakup. Others told authorities they received a Snapchat message from him late on the night of June 8 “that was suicidal in nature.”

Court documents also reveal Flores’ father told a Larimer County sheriff’s deputy that his gun, a .22-caliber revolver, was missing from his gun locker at home. He told investigators his son knew where the key was and that Flores may be headed for the unoccupied ranch in Collbran.

On the morning of June 10, Larimer County deputies contacted a woman who lives near that ranch, the arrest affidavit explains. She told them she could see a white truck in the driveway and a man who appeared to be Tanner Flores outside.

While on the phone with one of the deputies, the woman said she “saw a 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 affidavit also reads that witness “was not totally sure, but she thought she could see an arm sticking out of the bundle.”

The Mesa County Sheriff’s Office SWAT team responded to the ranch and established a perimeter. Investigators observed a male, but couldn’t see a female, according to the affidavit. At one point, investigators see the male throwing something into a field near the home, “believing it was a rag with potential blood on it,” the report reads.

SWAT officers eventually arrested Flores and discovered Doolittle’s body in the back of the truck.

Flores has not yet been formally charged, but is expected to be extradited to Larimer County soon.

Additional Information from the Doolittle Family:

To all of Ashley Doolittle’s friends and family. Thank you so much for all of the texts, Facebook messages, visits, and phone calls regarding Ashley. It has been a hard week but these notes have touched her entire family deeply. We have set up the arrangements for Ashley’s funeral this week and want to share the information with you in the event you would like to come by. Please share this information with anyone that knew Ashley. Thank you for your continued support and prayers! – Ann Marie Doolittle, Jeffrey Doolittle, Michael Doolittle

Viewing – Thursday, June 16 – 4 p.m. to 7 p.m. at Viegut Funeral Home, 1616 N. Lincoln Avenue, Loveland, CO

Mass (Funeral Service) – Friday, June 17 – 10 a.m. at St. John the Evangelist Catholic Parish, 1730 W. 12th St, Loveland, CO

Burial – Friday, June 17, directly following the Mass. Escort will take us to the Berthoud Cemetery located at the corner of State Highway 56 and County Line Road.

Reception – Friday, June 17, directly following the burial. Will be held at St. John the Evangelist Catholic Parish

In lieu of flowers, we ask that donations be made to the Ashley Doolittle Princess Program. This program is to help foster the love of rodeo in young girls who show an interest in the royalty community. This was Ashley’s dream when she was crowned and the royalty committee plans to continue her legacy. Her compassion and love of the rodeo will shine through this program and will influence future leaders in our fair, rodeo, and royalty communities.

Donations can be made to Boulder County Fair Royalty and sent to the Treasurer, Katie Richardson, at 758 S. Juniper Ct, Milliken, CO 80543.

Kelly Werthmann joined the CBS4 team in 2012 as the morning reporter, covering national stories like the Aurora Theater Shooting and devastating Colorado wildfires. She now reports for CBS4 News at 10 and is always open to story ideas. Connect with her on Facebook or Twitter @KellyCBS4.