CODY, Wyo. » Two teens charged in a triple homicide in a small Wyoming town told investigators they stole handguns from a Cody gun store and went to a house they knew to steal a black Audi SUV so they could escape to Denver.

Stephen Hammer, 19, and Tanner Vanpelt, 18, both of Cody, are making their first court appearance this morning in a case that has rattled residents of the small town of Clark near the Wyoming-Montana border.

Each is charged with 11 felony counts, including premeditated murder, use of a deadly weapon and robbery. Some of the charges could carry the death penalty.

They were arrested after neighbors described two men entering the house Saturday where the victim’s bodies were found. The neighbors saw two vehicles speeding away, including a black Audi belonging to Ildiko Freitas, 40, who owned the house with her husband. Freitas and her parents, Janos Volgyesi, 69, and Hildegard Volgyesi, 70, were found dead inside the house.

According to court documents filed today, after being arrested, Hammer told investigators they used two 9 mm handguns the pair stole last week from a Cody gun store and went to the house to steal the Audi and leave the state.

Vanpelt got into an argument with Freitas over the car and that’s when he pulled out a gun and shot her, according to the documents. Hammer then went into the basement after hearing something there and shot a woman he encountered, Freitas’ mother, Hildegard Volgyesi. Vanpelt told authorities he also went downstairs and shot the woman twice because it appeared she wasn’t dead.

When Vanpelt was taking the Audi, the two young men encountered Freitas’ father, Janos Volgyesi, in the garage and Vanpelt shot him twice in the back, the documents state.

After their arrest, Hammer and Vanpelt led investigators to an irrigation pipe several miles from the shooting scene where they had hidden the two 9 mm handguns.

It’s unclear how the teens knew about the Audi. Residents of Clark said Hammer used to live with his family in town but had moved away several years ago.

Hammer told investigators he was “sorry for shooting ‘that lady,'” according to the documents. Vanpelt said “they had not planned it to go down this way.”

Freitas grew up in Bakersfield, Calif., and attended the University of Wyoming before moving to Clark with her husband six or seven years ago. Last year, the couple bought another house in Loveland, Colo., that they had been renovating and were planning to move into sometime soon, said neighbor David Mathiesen.

Vanpelt’s father, Robb Vanpelt, said Monday that his son was not living with him and had not been in serious trouble before his arrest, which was “pretty much totally out of the blue.”

Tanner Vanpelt graduated in December 2011 from Cody High School, where principal Brandon Jensen recalled that the teenager wasn’t involved in athletics or after-school clubs, but also never had serious discipline issues.

Hammer attended the school only a year before transferring during his freshman year, Jensen said.

Residents of Clark said it’s the first murders they can recall in decades in the rural community dominated by agriculture that sits near the Clarks Fork of the Yellowstone River.