A member of the 1980 "Miracle on Ice" hockey team that won Olympic gold for the United States is jailed in northeastern Minnesota on charges that he attacked a neighbor with a metal pole.

Mark Pavelich's sister says his aggression is uncharacteristic and may be related to head injuries suffered on the ice, including during his career in the National Hockey League.

Pavelich was booked into the Cook County jail last Thursday night and appeared Monday in Cook County District Court on charges of second- and third-degree assault, possession of an illegal shotgun and possessing a gun with a missing serial number.

Pavelich, 61, a land developer in Lutsen, remains held in lieu of $250,000 bail and was ordered by District Judge Michael Cuzzo to undergo a hearing on his mental competency to stand trial.

Cuzzo wrote that based on the allegations he sees "sufficient probable cause" for the court to have "reason to doubt [the] defendant's competency to understand the proceedings against or to participate in his own defense."

Grand Marais attorney Tyson Smith appeared on Pavelich's behalf at the five-minute hearing. Smith said Pavelich's mother and sister were there as well. Smith otherwise had no comment and said he expected Pavelich would be hiring someone else to represent him as the case proceeds. Pavelich is scheduled to be back in court on Oct. 20.

Pavelich's sister, Jean Gevik, said the family is convinced that "all the concussions and the blows he had in the NHL" left Pavelich suffering from CTE, or chronic traumatic encephalopathy, a degenerative brain disease that has been linked to erratic behavior and deaths among hockey and football players and others in sports that inflict trauma to the head.

"Mark is the most kind and gentle person you'd ever know," said Gevik, who teaches in the Twin Cities and spends summers near Pavelich's home on property that her brother gave her. "This is a totally different guy."

The Sheriff's Office said its deputies were dispatched on a call from the victim about the assault. James T. Miller, 63, reported being struck with a 3- to 4-foot-long metal pole by Pavelich after returning from a full day of fishing to the hockey star's home in a remote area several miles down a dirt road near Deer Yard Lake. Pavelich had accused Miller of "spiking his beer," the criminal complaint read.

Miller was hospitalized in "a tremendous amount of pain" and suffering from two cracked ribs, a bruised kidney and a fracture to one of his vertebrae, along with possible internal bleeding, the charges detailed. The beating also left bruises on his arms and legs and a large mark across his back.

Gevik said she started seeing changes in her brother two to three years ago, specifically with "anger issues, damaging property." She added, "He never hurt anybody, not even in the NHL," where he played somewhat undersized at 5 feet 8 inches, 175 pounds, and only occasionally got in fights.

"Even when he'd get battered around, he'd never retaliate," she said.

Gevik said that Herb Brooks, Team USA's coach at the 1980 Games and later in the NHL with the New York Rangers, once recalled that "Mark had one very bad head injury that he was surprised Mark lived through."

Gevik said that since she started worrying about her brother she's been consulting with an expert working with some former National Football League players with similar psychological difficulties.

"All the research is out there about CTE," she said. "This should not be a surprise here."

Gevik said she was pleased when the judge ordered that Pavelich be examined for any mental or psychological difficulties. "He needs medical care," she said, while also understanding that CTE can only be confirmed in a post-mortem examination. "Maybe now he can get the help he needs."

The NHL has faced criticism for its handling of head injuries despite a long list of rules, studies and league-player committees focused on enhancing player safety.

The league reached a court settlement last year with hundreds of retired players who claimed harm from head injuries while playing, but the NHL admitted no fault or wrongdoing. Each player who opts in would receive $22,000 and could be eligible for up to $75,000 in medical treatment. Pavelich has not made a claim, his sister said.

According to the charges and other court filings:

Deputies arrived at Pavelich's home and in the yard found the pole, resembling a tension bar, that they say was used to beat Miller.

Inside, a shotgun was found under a bed upstairs and seized by a member of the U.S. Forest Service. The butt of the gun was gone and replaced with a bent tree branch, leaving the weapon shorter than the legal limit. Its serial number had been scratched off.

Pavelich was arrested at the entry to his home. Miller made it back to his house and was going "in and out of shock," the charges read.

Pavelich has been a virtual recluse away from the ice since he and his fellow amateur skaters channeled David and stunned Olympics watchers with their "Miracle" victory over the game's then-Goliath, the Soviet Union. That semifinal triumph in the Olympics propelled Pavelich and his teammates into modern sport immortality and onto the gold medal stand in Lake Placid, N.Y.

Pavelich, the creative center who starred for Eveleth (Minn.) High School and the University of Minnesota Duluth, assisted on Mike Eruzione's winning goal against the Soviets. Team USA'S story was turned into the Hollywood hit movie "Miracle" in 2004.

Pavelich soon moved into the NHL, playing five seasons with the Rangers and scoring 99 goals in the first three seasons. He joined the Minnesota North Stars in 1986-87, but only for 12 games.

After a brief pro stint in Italy, he was out of the game before a career-ending two-game stint with the San Jose Sharks in 1991-92. His time in the NHL spanned 355 games, tallying 137 goals and 192 assists.

In 2012, Pavelich's 44-year-old wife, Kara, died in an accidental fall from a second-story balcony at their home. Two years later, Pavelich sold his gold medal for $262,900 through a Dallas-based auction house, explaining that he was not in financial trouble and just wanted to provide financial security for his adult daughter.

Correction: A previous version of this story included a headline that misstated Pavelich's first name.