MANKATO - The lawyer for former University of Minnesota quarterback Philip Nelson said in a court hearing Monday that no one can prove his client was the one who nearly killed a Mankato man in a booze-fueled fight last May. He requested criminal charges against his client be dismissed.

Nelson can be seen in a surveillance video recording kicking Isaac Kolstad in the head, but Kolstad was also sucker punched by another man, then hit his head on the pavement when he fell and also vomited, cutting off his air supply and causing brain damage, said defense attorney Jim Fleming.

“They can’t say what injuries [Nelson] caused,” said Fleming.

The hearing before Blue Earth County District Court Judge Bradley Walker included new details about the May 11 fight, including that both Nelson, who was 20 at the time, and Kolstad, who was 24, were intoxicated; Nelson had a blood alcohol content of 0.12 and Kolstad was at 0.16, according to police testimony. Fleming also circled back again to evidence that shows Kolstad threw the first punch and that he taunted Nelson by claiming to have slept with his girlfriend.

The fight left Kolstad, a husband and father who worked as a salesman for Fastenal, with a severe brain injury. He recovered sufficiently to walk onto the Mankato State football field with his old teammates at one game this fall, but he struggles to speak and faces an uncertain future of continued therapy and treatment, according to his CaringBridge website.

Nelson, a high school football star from Mankato who started at the University of Minnesota for two seasons, was kicked off the Rutgers University football team days after he was criminally charged. He faces two felony counts of assault and could spend up to 20 years in prison if convicted.

The hearing Monday comes more than six months after Kolstad and Nelson met at the intersection of Cherry and Front Streets as bars closed in the city’s entertainment district. The two men were in a heated argument moments before the fight, which took place shortly after 2 a.m.

A friend of Kolstad’s who was with him that night testified Monday that he heard Kolstad and Nelson arguing about something but couldn’t make out exactly what was being said. Samuel Thompson, a friend of Kolstad’s who also knew Nelson, said he tried to defuse the situation by walking Nelson 20 to 30 feet away from Kolstad. He confirmed that Kolstad then rushed at the two of them.

“Isaac came over behind me and attempted to throw a punch,” said Thompson. He said he didn’t know if he or Nelson was actually hit by Kolstad’s fist, but that he fell down and took Nelson down with him.

It was another man, Trevor Shelley of St. Peter, who then allegedly punched Kolstad in the head, knocking him out and causing him to fall headfirst to the ground. Shelley faces first and third-degree assault charges.

Thompson said he also witnessed Nelson kick Kolstad in the head with a “windup kick” to the left side of Kol­stad’s head.

Two police officers who testified Monday said they found Kolstad lying unconscious on the street surrounded by witnesses, several of whom identified Nelson by name. Nelson was found nearby as he walked away with his girlfriend. He told officers he didn’t understand why he was being arrested, said Mankato police officer Robert Sadusky.

Nelson also denied hitting or kicking anyone that night, Sadusky said. The police still have Nelson’s shoes from that night, a pair of black-and-white Nikes, and Sadusky showed them to Fleming when asked.

Fleming concluded his arguments by saying his own medical expert, Dr. Daniel Davis, concluded that it was Shelley who caused most of Kolstad’s injuries. Davis was not present for the hearing Monday.

The Mankato neurosurgeon who treated Kolstad, Dr. Dominic Cannella, said Kol­stad’s injuries were caused by a combination of blows to the head and a lack of oxygen from choking on his own vomit, a point that Fleming raised with the lead investigator in the case, Mankato police detective Jason Bennett.

“Cannella was unable to assign a percentage of who was more or less responsible for Isaac Kolstad’s injuries,” said Fleming. “Correct,” said Bennett.

Fleming argued that a surveillance video that shows Nelson kicking Kolstad in the head is evidence only of assault, not that he caused “great bodily harm” or “substantial bodily harm,” the respective thresholds for felony charges of first degree and third degree assault.

Blue Earth County Prosecutor Patrick McDermott said the police and medical records show sufficient evidence to charge Nelson, but that it will ultimately be up to medical experts and a jury.

“From the very beginning of this case I said this case is going to come down to medical testimony,” said McDermott.