Montana Marlatt allegedly turned a shotgun on his brother after fatally shooting a man in a deserted area southeast of Madras on Sunday, according to documents filed in Jefferson County Circuit Court.

Marlatt, 24, is being held on charges of murder and manslaughter in the death of 19-year-old Devon Moschetti of Madras. A grand jury returned an indictment against Marlatt on both charges late Tuesday; he is scheduled to be arraigned Thursday.

In an affidavit laying out the case for Marlatt’s arrest, Jefferson County Sheriff’s Sgt. Jason Erickson described the version of events investigators were able to piece together on the afternoon of the shooting.

According to the affidavit, Marlatt was at the Tiger Mart on Madras’ south side Sunday afternoon when he met his brother — McKenzie Brown — and Derick Summerhalder, both 19, and Moschetti.

Marlatt had been waiting for a bus to Redmond, but instead joined the group to go shooting. The four stopped at Bi-Mart to purchase ammunition and headed out U.S. Highway 26 toward a large rock wall in the Crooked River National Grassland.

Upon arrival, Marlatt exited the vehicle and climbed to the top of the rock wall, three to four stories above the surrounding terrain. The other three men took turns shooting two shotguns and a handgun.

When Marlatt returned from climbing, he got a shotgun from Summerhalder. He turned and looked at Moschetti, and according to the affidavit, said something similar to “who are you?” and fired.

Marlatt fired a second shot as Moschetti fell to the ground, the affidavit states. Moschetti was struck in the face and the chest, though it is unclear which shot was fired first, according to Erickson.

Marlatt then turned on Brown with the shotgun. Brown pointed a pistol at Marlatt and said something similar to “what the f— did you do?” Erickson wrote. With that, Marlatt dropped the shotgun and ran off to the southeast.

Sheriff’s deputies located and detained Marlatt shortly after 2 p.m., about 40 minutes after dispatchers received a 911 call reporting the shooting.

Kathie Rohde, aunt to both Marlatt and Brown and a friend of the Moschetti family, said: “None of this makes any sense to us.”

“This is totally out of character for Montana,” she said Tuesday.

Rohde said Marlatt until recently had worked at the Brightwood wood products plant in Madras. She said he’d been living in the Madras area for the last year, and has a 4-year-old daughter.

“All through his life I think he was a good kid,” she said. “I didn’t know him to have any tendencies to do anything like this, as his aunt.”

A review of state court records indicates Marlatt had a handful of run-ins with the law in recent years.

In June 2010 in Wheeler County, he was charged with fourth-degree assault, strangulation and menacing, but the charges were dropped a month later. Marlatt was under a restraining order stemming from the same incident for 10 months, until the woman who had requested the order had it withdrawn. The same woman initiated a formal separation from Marlatt in January 2012, then halted the proceedings two months later.

Also in June 2010, Marlatt was charged with felony possession of methamphetamine in Jefferson County. Criminal charges were dismissed when he successfully completed drug court diversion in August 2011.