A second man charged in a nasty Mankato fight that left another man hospitalized with brain injuries bragged that he "wound up and hit him as hard as he could," according to a criminal complaint filed Wednesday.

Trevor Shelley, 21, of St. Peter, Minn., appeared in Blue Earth County District Court and was later released on $20,000 bail. The bail and charges of first- and third-degree assault mirror those leveled against former Minnesota Gophers quarterback Philip Nelson, who appeared in court two days earlier for his alleged involvement in the same altercation early Sunday morning in Mankato's downtown bar district.

Isaac Kolstad, 24, remains in critical condition with a fractured skull and other injuries sustained when Shelley's punch allegedly knocked him unconscious. Nelson, 20, stands accused of kicking Kolstad in the head as he lay defenseless on the pavement.

According to the complaint, Shelley arrived at a Mankato house about 3 a.m. Sunday wearing a torn red shirt that was "halfway off." Someone who knew Shelley and Nelson, both who attended Mankato West High School, told police that Shelley said he'd been involved in the fight about an hour earlier.

"Shelley told him that he was downtown, and that he walked up to someone that was 'starting something' with Nelson, and 'wound up and hit him as hard as he could," the complaint reads.

That person told police he was "100 percent" certain that Shelley was the person seen fleeing in a torn shirt on surveillance camera video that police released Monday as they searched for a second suspect.

Another witness, who gave Shelley's name to police, said he grabbed Shelley's shirt and tore it during the scuffle. Despite a police review of video they say shows Shelley punching Kolstad — rendering him limp and collapsed on the sidewalk — Shelley denied ever hitting him.

When authorities asked Shelley if he had struck Kolstad, he "stated that he did not," the complaint said. Told that surveillance cameras in the area might have captured what happened, "Shelley maintained that he did not hit anyone."

The whole clash, which only lasted a matter of seconds, started with a heated argument. Nelson was apparently upset that a bouncer kissed his girlfriend's hand earlier, and authorities say he might have confused that bouncer with Kolstad.

Shelley told police that he was leaving Blue Bricks Bar at closing time when he saw Nelson, his girlfriend and another man. Shelley says Kolstad first struck Nelson, knocking him over — an account verified by the police officer who studied the video.

Shelley said the other unidentified man in a black shirt tore his red shirt as he tried to get away from the area.

Kolstad, a young father and a former football player at Minnesota State, Mankato, suffered a fractured skull, brain bleeding and lung issues after being knocked out.

A fund created to help the Kolstads has already raised more than $27,000. More info is at tinyurl.com/nv4q3ya.

Curt Brown • 612-673-4767