Chai Vang, 36, of St. Paul, Minn., could get life in prison if convicted in the shootings, which left six people dead and two wounded. Wisconsin does not have a death penalty.
The gunfire broke out Nov. 21 after Vang was caught trespassing on a hunting platform on some of the victims' land.
In court papers, Vang, a Hmong immigrant from Laos, said that he opened fire after the others took a shot at him first and berated him with racial slurs. But two of the survivors told authorities that Vang fired the first shot.
Vang is jailed on $2.5 million bail.
Wisconsin state investigators have questioned some men who were hunting with Vang the day eight hunters were shot, six fatally. Police in St. Paul say two investigators from the Wisconsin Department of Justice traveled there last week to question some Hmong men. But no one was taken into custody.
Vang was arrested about four hours after the shootings last week as he emerged from the woods with his empty SKS 7.62 mm semiautomatic rifle.
Sawyer County Sheriff Jim Meier said a dispute over Vang's use of a tree stand — a raised platform used by hunters — on private property preceded the gunfire.
Vang told investigators he didn't realize he was on private property when he climbed the tree stand, according to the probable-cause statement released Tuesday. The county has thousands of acres of public hunting land, some of it "virtually around" the private property where the shooting occurred, Meier has said.
A hunter approached and told Vang he was on private property, and Vang started to leave as other hunters approached, the statement said. Vang said the hunters surrounded him and some called him racial slurs.
Vang said he started walking away but looked back to see the first hunter point his rifle at him and then fire a shot that hit the ground 30 to 40 feet behind him, the statement said.
Vang told investigators that's when he started firing at the group, according to the statement.
Five people died at the scene and a sixth died Monday in a hospital. Two others were wounded. The dead were identified as the landowner, Robert Crotteau, 42; his son Joey, 20; Al Laski, 43; Mark Roidt, 28; Jessica Willers, 27; and Denny Drew, 55, who died Monday at St. Joseph's Hospital in Marshfield. Willers' father, Terry Willers, remained hospitalized Tuesday in fair condition, while the other wounded hunter was released.
Officials said the victims were part of a group of 14 or 15 who made their opening-weekend trip to the 400-acre property an annual tradition.
"This was his first time out with that group. He was delighted to be invited," said Karen Roidt, mother of victim Mark Roidt.
According to an account Meier gave Monday, two or three hunters spotted a man in a hunting platform on Crotteau's land, then radioed back to the rest of the party at a nearby cabin and were told no one should be there. Meier did not indicate who the account came from.
One of the men asked the intruder to leave, while Crotteau and the others in the cabin hopped on their all-terrain vehicles and headed to the scene, according to the account.
"The suspect got down from the deer stand, walked 40 yards, fiddled with his rifle. He took the scope off his rifle, he turned and he opened fire on the group," Meier said.
He was "chasing after them and killing them," Deputy Tim Zeigle said. "He hunted them down."
Authorities have said there was only one firearm among the eight hunters and it was unclear whether anyone returned fire.
Some Hmong leaders questioned whether racial differences may have figured in the shootings.
There have been previous clashes between Southeast Asian and white hunters in the region. Locals in the Birchwood area, about 120 miles northeast of the Twin Cities, have complained that the Hmong do not understand the concept of private property and hunt wherever they see fit.
Sang Vang said his brother has lived in the United States for more than 20 years and is a U.S. Army veteran.
Vang's arrest made some Hmong citizens in his hometown fearful of a backlash. Hmong leaders in St. Paul condemned the shootings Tuesday and offered condolences to victims' families.
"What happened in Wisconsin is in no way representative of the Hmong people and what they stand for," said Cha Vang, who said he was representing "the greater law-abiding Hmong community." He is no relation to Chai Vang.
About 24,000 Hmong live in St. Paul, the highest concentration of any U.S. city.
Minneapolis police said they arrested Chai Vang on Christmas Eve 2001 after he waved a gun and threatened to kill his wife. No charge was filed because she didn't cooperate with authorities, spokesman Ron Reier said. St. Paul police said there had been two domestic violence calls to his home in the past year, but both were resolved without incident.