As Notre Dame sees it, Manti Te’o was the victim of a social media hoax so cruel that Fighting Irish athletic officials initially wondered whether criminal activity was involved.

Instead, the university said it’s simply an embarrassing chapter for Te’o, the linebacker who became a fan favorite and Heisman Trophy finalist by overcoming an early-season tragedy when his grandmother and the woman he believed was his girlfriend died on the same day.

The relationship existed only online, but the woman wasn’t real, Te’o learned and a private investigation firm hired by the university confirmed.

“This was a very elaborate, very sophisticated hoax, perpetrated for reasons we can’t fully understand, but it had a certain cruelty at its core,” Notre Dame athletic director Jack Swarbrick said.

Swarbrick called a news conference on Wednesday night to respond to a story by Deadspin.com, a sports culture and gossip website, which reported Te’o’s girlfriend, Lennay Kekua, did not actually exist.

The story of Te’o and Kekua was long-standing and contained many layers: They met while she was a Stanford student and the Irish played there in 2009, she was in an auto accident this summer and died of leukemia on Sept. 12.

As Te’o and Notre Dame’s season excelled, stories about their relationship started to appear in mainstream publications, and when Kekua supposedly died — on the same day that Te’o’s grandmother actually died in Hawaii — Te’o publicly said it had been difficult to focus on football.

“Yeah, it was definitely hard,” Te’o said during Notre Dame’s weekly news conference on Oct. 3. “That had to be the hardest thing that I’ve had to do so far, to be able to operate, and to be able to try to continue with my daily routine, but knowing that I just lost a woman that I truly loved. That was the hardest thing.”

Te’o said that he was inspired the morning of the Michigan game on Sept. 22 because that was the day Kekua’s casket was closed. He gave an emotional speech at a pregame pep rally and thousands of Notre Dame fans wore Hawaiian leis in the stands as the Irish won 13-6.

“I had a moment then,” Te’o said.

But Te’o had never physically met his girlfriend, Swarbrick learned in a meeting with the linebacker on Dec. 27. By then, Te’o had known for about three weeks that he probably had been duped.

According to Swarbrick, Te’o was attending the College Football Awards show in Orlando, Fla., in early December when his cellphone rang and posted the same number that he once believed was Kekua’s.

The female voice on the line — the same voice that Te’o had believed to be his girlfriend’s — said she was still alive.

Swarbrick said Te’o was unnerved and told his parents. He didn’t inform the coaches until Dec. 26, and Swarbrick was brought into the loop the next day.

“When Manti took me through the entire story, start to finish, he first described the contact (with Kekua) as ‘met,’ ” Swarbrick said. “It was an online meeting.”

Swarbrick didn’t share specifics of the investigation but said there were “a remarkable number of characters involved. We don’t know how many people they represent. There are male and female, brothers, cousins, mother. We don’t know if it’s two people playing multiple characters or multiple people.”

In the early stages of discovery, Notre Dame feared possible criminal activity and wondered about motive. Was somebody trying to extort future earnings from Te’o, who figures to become a first-round draft choice in April’s NFL Draft?

Swarbrick said the university considered but did not alert the police. The school received the findings of the investigation on Jan. 4 and shared them with Te’o’s parents on that day. Three days later, the Irish lost to Alabama 42-14 in the championship game.

Although Notre Dame knew about the hoax as the Irish prepared for the game, Te’o was encouraged to speak about the game when asked about that chapter of his life. Swarbrick said the Te’os had planned to reveal the story as soon as next week.

Te’o issued a statement on Wednesday and is expected to speak with reporters as soon as today, Swarbrick said.

“To realize that I was the victim of what was apparently someone’s sick joke and constant lies was, and is, painful and humiliating,” Te’o said. “It further pains me that the grief I felt and the sympathies expressed to me at the time of my grandmother’s death in September were in any way deepened by what I believed to be another significant loss in my life.”

Te’o likely will be asked about comments by his father, Brian, who was quoted by the South Bend Tribune as saying Kekua had flown to Hawaii to visit Manti.

Swarbrick said as part of the hoax, “several meetings were set up where Lennay never showed, including some in Hawaii.”

At one point, Swarbrick appeared to have choked up. He paused to sip some water and continued.

“The single-most trusting human being that I’ve ever met will not be able to trust in the same way again in his life,” Swarbrick said. “That’s an incredible tragedy.”