Two men have pleaded guilty to charges that they attacked a third man on May 22.
Both defendants signed plea agreements last month with federal prosecutors.
Investigators say Colin Dean Amos and John Goodman came to Joshua Rosenberger's door a little before 8 p.m. May 22 in the 900 block of Rendezvous Road.
After a disagreement, Amos and Goodman attacked Rosenberger with a large file and a shovel, respectively.
Amos pleaded guilty on Sept. 9 to assault that resulted in serious bodily injury.
Goodman pleaded guilty Aug. 28 in U.S. District Court in Casper to assault with a dangerous weapon.
A grand jury in June charged both men with the crimes. Both men face up to 10 years in prison, but the plea agreements could limit their potential penalties. Details of the agreements are not public.
The defendants will be sentenced at a later date.
FBI special agent Jordan Pyle, who investigated the case, said the defendants, along with witness Jamie Goodman, went to Rosenberger's house May 22 to ask for a ride. Rosenberger told the three they had to leave because they were drunk.
The two Goodmans and Amos then tried to enter the home, Pyle said. John Goodman and Amos became angry and attacked Rosenberger. Amos punched the man, and John Goodman tackled him, Jamie Goodman told Pyle.
Then John Goodman picked up a wooden-handled spade from Rosenberger's porch and struck Rosenberger with it, Jamie Goodman told Pyle. She saw Amos grab a "metal stick" and hit Rosenberger with it as well.
Rosenberger's wife, Nicole Goodman, told the alleged attackers she was calling the police, and they fled into a nearby field, Pyle said. She then drove her husband to SageWest Health Care at Riverton because his head was bleeding.
"I was hit with a piece of metal," Rosenberger told emergency room doctor David Bender. "I felt a crunch. My head felt like a soft tomato."
Bender told Pyle that Rosenberger had suffered a cut artery in his head and a fractured skull. Rosenberger could have died from the bleeding if he had not been treated, the doctor told Pyle.
The Rosenberger home is on the Wind River Indian Reservation, and both defendants are members of the Northern Arapaho Tribe, Pyle said. Federal investigators and prosecutors typically handle cases on the reservation that involve American Indians.