To Kosta Karageorge, to lose was to fail and he hated failure. In the eighth grade, when he didn’t make it to the state wrestling championship, he refused to wash from his hand the number designating his weight class. He wanted to memorialize his defeat so he would never forget what it felt like.

On Sunday, the 22-year-old Ohio State University athlete, a top-rated wrestler and a walk-on football player, was found dead in a dumpster from an apparent self-inflicted gunshot wound days after he was reported missing, authorities said.

“Everything he did, his whole heart was into it,” teammate Johnni DiJulius told NBC4. “He always went all the way, all in. He never just half did something. Now it’s just hard to believe that he’s gone.”

Karageorge went missing on Wednesday.

The 6-foot-5, 285-pound Buckeye texted his mother, Susan Karageorge, at about 1:30 a.m. “I am sorry if I am an embarrassment but these concussions have my head all f—ed up,” he wrote. His mother told police her son had suffered from concussions and confusion in his short career. He wrestled in high school and then for three years at Ohio State before joining the university’s football team in August as a walk-on defensive lineman.

“He had a pretty bad concussion last fall and he told me about differences in his behavior,” his sister, Sophia Karageorge, told the New York Times last week. “Just, like, confusion, disorientation, being unable to focus, mood swings — not feeling like himself, basically, not feeling quite right.”

She added: “And he was never one to risk it, after he realized how seriously it could affect him.”

On Wednesday, Karageorge left his apartment in Columbus, Ohio, less than a block from campus. His roommates said he went for a walk. His sister said he was dressed in all black, wearing black sweatpants over his jeans, black boots, a black beanie and a black hoodie. He didn’t take his motorcycle or his wallet.

He didn’t show up for football practice that day. He didn’t show up for the final home game Saturday against the team’s archrival, the Michigan Wolverines. Karageorge, along with other senior players, was supposed to be recognized at the game. The stadium fell silent as Karageorge’s name was read and his missing person’s flier was projected on the Jumbotron.

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“We’re very concerned that he’s not himself and that he maybe doesn’t know what’s going on,” Karageorge’s sister told the Columbus Dispatch last week.

Jim Borchers, a Buckeyes physician, said he could not comment on student athletes’ medical care, but said, “We are confident in our medical procedures and policies to return athletes to participation following injury or illness.”

On Sunday afternoon, a woman and her son found Karageorge’s body while rummaging through garbage in a dumpster around the corner from his apartment. A handgun was also discovered in the trash bin, authorities said.

“It’s devastating. It’s something you don’t prepare for,” 21-year-old senior Craig Thomas told the Columbus Dispatch. Thomas was on the wrestling team with Karageorge at Ohio State and has known him since high school.

Karageorge wrestled for Thomas Worthington High School in Worthington, Ohio, less than 10 miles from Columbus. The summer before his senior year, he trained with the Belarus Olympic wrestling team, which was preparing for the 2012 Olympic Games. He was 16.

Asked whether he got homesick that summer, Karageorge said no. “I figured I wasn’t missing much here anyway,” he told local newspaper ThisWeek.

Karageorge weighed 240 pounds when he got home. And by the beginning of the high school varsity wrestling season, he weighed 290.

“It wasn’t just his technique, it was his attitude,” his high school wrestling coach, Jeremiah Webber, told the local newspaper in 2010. “He was 100 times more aggressive, more active and more intense. His attitude completely changed.”

His senior year, Karageorge was an undefeated heavyweight up until the second round in the state tournament. After graduation, he accepted a wrestling scholarship at the University of Oklahoma before enrolling in Ohio State, where he competed for three years.

The redshirt senior walked on the football team this season and played in a game against Penn State.

On Sunday night, some 400 students attended a prayer vigil for Karageorge on campus as the Ohio State marching band played a tribute. About 10 stepped forward to share stories. Some said he was the guy to call when your car broke down or when your drunk friend needed to be carried home, the Plain Dealer reported.

“I have known him for four years now,” fellow senior and wrestling teammate Matthew O’Hara told the university’s student newspaper, the Lantern. “There is really only one word — that is ‘passion’. Absolute passion in everything he did, whether that was wrestling or football, or his friends and family.”

Ohio State head football coach Urban Meyer sent out a tweet Sunday night, saying “Our thoughts and prayers go out to Kosta’s family. He will be missed.”

His teammates took to social media as well.