If one had to limit their description of Super Bowl LII to just one word, “upset” might be the most appropriate. The showdown, between one of the best quarterbacks in NFL history in Tom Brady and a backup in Nick Foles, was a blowup. Somehow, Foles and the Eagles sent the Patriots home with an “L.”

The Brady/Belichick-era Patriots had more than their share of wins. But a Super Bowl is a Super Bowl; losing one still hurts the team and fans. The moment that always gets brought up is the inexplicable benching of one Malcolm Butler. How could a top-flight cornerback, who came up huge in the Super Bowl before, end up watching the game from the sidelines?

Malcolm Butler’s strange benching

Butler’s absence in Super Bowl LII isn’t just one of those moments that fans glom onto out of a pure need to look for answers. He came up big in a similar moment before — at Super Bowl XLIX. The cornerback intercepted a pass at the goal line, which turned out to be the dagger in the Seattle Seahawks‘ offense.

He was also instrumental in Super Bowl LI. That year, the Patriots held their ground against the Atlanta Falcons and a 25-point deficit. Butler was on the field for much of that.

The following year, Belichick made what is unquestionably the most baffling decision of his career, as NBC Sports details. As the game slipped away from the Patriots, Malcolm was stuck as a spectator for the entire run. A proven clutch cornerback, available in a situation where a (incredibly talented) backup QB was putting his squad away in a championship game.

What Butler’s friend and former teammate Shane Vereen has to say

While rumors abound, no one can explain why Malcolm was benched, to this day. That includes his former teammates. Former NFL running back Shane Vereen was there when Butler made that incredible catch that sealed his legacy in Patriots history.

He was also there, playing himself, noticing a prominent absence as the game ran away from his team. Whatever the decision was, Vereen wasn’t in the loop. What’s weird, though, is that years of trying hasn’t gotten the current free agent RB any answers.

“No, I have actually asked quite a few guys who were on the team at the time,” Vereen told CBS Sports, “and I have not got the same answer twice.” Conspiratorially, he added, “the grassy knoll still exists.” That last bit, implying some kind of unknowable conspiracy, is telling. Whatever ran through Belichick’s mind, the only people who know aren’t willing to say.

Did Butler ever learn why he was left on the bench?

One recurring rumor on the situation is punitive. Tabloid reports after the Patriots’ loss pointed towards Butler being iced over supposedly partying too hard in the lead up to the big game. That rumor has been shot down repeatedly by everyone involved, including Vereen.

Adding to the confusion on this point, it appears whatever Butler did to get on Belichick’s bad side happened before the game. Safety Devin McCourty, one of Belichick’s few player-confidants, says he knew before the game that Belichick wouldn’t use Butler. Yet even he doesn’t know why.

Does Butler himself have any insight? Even after all this time, he’s left grasping at straws. In his own CBS Sports comments, he only mentions that he missed the first day of Super Bowl Week celebrations. Even former Patriots golden boy Brady was left in the dark.

“[Brady] was really concerned, and he just wanted to know what was going on or whatever,” Butler said of Brady’s series of phone calls after their shocking loss. “I really appreciate that from him.” If Brady doesn’t know, and Butler doesn’t know, we might have to wait on Belichick’s retirement memoirs to truly understand what was behind one of the strangest decisions of his career.