Two groups of men allegedly traded a homophobic slur outside the State Fair before a St. Paul man punched another man in the head, leaving his victim critically injured and suffering from brain damage, according to charges.

Gunner D. McClellan, 21, was charged Thursday in Ramsey County District Court with one count of felony first-degree assault for allegedly attacking Michael Donnelly on Sept. 1. Donnelly, of Little Canada, was 48 at the time.

"[Donnelly] must wear a protective helmet whenever he is not in bed to protect his brain as the portions of his skull that were removed have not yet been replaced," according to the charge. "[Donnelly] requires near constant care and has not been able to return to work."

The criminal complaint alleges that two women who know McClellan and his friend told police that the two men used a homophobic slur and another derogatory term against Donnelly and his friends.

One of Donnelly's friends told police that someone in their group also used the same slur against McClellan's group. It's unclear who started the verbal altercation.

In an interview with police, McClellan's friend denied saying anything to Donnelly's group and alleged that the other group used the slur. The friend also said Donnelly's group approached them, prompting him and McClellan to follow them.

St. Paul police spokesman Steve Linders said that the incident was not classified as a hate crime because neither Donnelly nor his two friends identify as LGBTQ.

According to the criminal complaint: Donnelly and his two friends had spent the evening at the State Fair and Donnelly was going to drive them home. They passed a group gathered outside a house.

People from the house started yelling at Donnelly's group. The two groups exchanged words, and Donnelly's group continued walking. McClellan and his male friend allegedly followed and harassed them.

Donnelly's group told the two men to stop following, and that they were not going to fight.

McClellan's friend punched one of Donnelly's friends about six times. A second friend of Donnelly's intervened. McClellan allegedly punched Donnelly once in the face, sending him to the ground "like a ton of bricks."

Found in an alley

Police found Donnelly about 12:30 a.m. lying on his back at the end of an alley on Albert Street between Como and Breda avenues. He was hospitalized in critical condition with bleeding and swelling in his brain.

Part of Donnelly's skull was removed to alleviate the pressure from the swelling, and an incision later became infected. Donnelly's friend who was also attacked suffered a black eye, an abrasion to the forehead and a bump above his left temple.

Three women who were at the house with McClellan and his friend spoke to police. People at the house had been drinking, and at least some had also come from the State Fair.

One woman told police that either McClellan or his friend yelled at Donnelly's group.

Another woman said McClellan and his friend yelled a homophobic slur at Donnelly's group, and that they ignored her efforts to stop their behavior.

A third woman told police that McClellan and his friend used a homophobic slur against Donnelly's group.

"Hey, calm down — we're just walking by," Donnelly's group said, according to the third woman.

The third woman also told police that McClellan and the other suspect had picked fights with people since they were 15.

McClellan's friend remains under investigation but has not been charged for his alleged role.

McClellan told police that someone in Donnelly's group had called his friends a derogatory name (not the homophobic slur), the complaint said. He allegedly said that's when he and his friend confronted Donnelly's group.

McClellan told an investigator that someone in Donnelly's group ran at and grabbed McClellan's friend, prompting a fight. McClellan also alleged that another man in Donnelly's group swung at him, causing him to throw a punch.

"We are happy that there's been an arrest made in this senseless act," said Donnelly's mother, Beverly Donnelly. "Mike is struggling on a daily basis."

Donnelly's family plans to hold a fundraiser for him from 1 to 6 p.m. on Jan. 27 at the Hoggsbreath Bar, 2504 Rice St., in Little Canada. A GoFundMe campaign has also been set up.

Chao Xiong • 612-270-4708 Twitter: @ChaoStrib