Kentucky head coach John Calipari argues with referee John Higgins in the South Regional final game against North Carolina in Memphis. (AP)

The anger went nuclear shortly after the final buzzer.

The end of the Elite Eight matchup between the University of North Carolina and the University of Kentucky in March in the NCAA men’s basketball tournament was a heart-stopper — with seconds on the clock, the Tar Heels’ Luke Maye landed a two-point jump shot, giving UNC the win and killing off the Wildcat’s March Madness hopes.

But at the news conference following the loss, Kentucky’s losing coach, John Calipari — one of the biggest names and highest earners in college basketball — did not launch into comments about lazy defense or bad play calls. He blamed the referees for the loss.

“You know, it’s amazing that we were in that game where they practically fouled out my team,” the coach told reporters. “Amazing that we had a chance.”

Calipari did not have to name names. Across the team’s rabid fan base, blame for the upset was already being heaped on the three officials calling the game, referees who had tapped the Wildcats with 19 fouls in the game, including two for each of Kentucky’s three star players in the first half alone.

In the days following the loss, the ill-will online and on sports talk radio clamped down on one referee in particular, John Higgins, the “most traveled, most recognized, most wanted, most mocked and most loathed referee in college basketball,” according to Sports Illustrated.

But the postgame outcry was not normal, veering away from sporting fun to straight harassment, according to a federal lawsuit filed Tuesday in Nebraska by Higgins and his wife, Carol.

The legal complaint says Kentucky fans were so irate over the Elite Eight finish they viciously harassed Higgins and his family, including clogging his roofing business with negative comments and even threatening the referee’s life. When Higgins returned to the court to referee the 2017 NCAA championship game, he had to be protected by a bodyguard.

Blame for the harassment, according to the complaint, lies with the lawsuit’s defendants, a Kentucky sports radio station and an on-air host, Matt Jones. Not only did the station stoke fans’ anger, it shared Higgins’s contact information online, causing “Mr. and Mrs. Higgins distress so severe that no reasonable person should be expected to endure it,” the suit says.

On Tuesday, Jones responded to the legal complaint on Twitter: “The Higgins lawsuit against KSR is frivolous and without any legal merit whatsoever. We will defend it and expect a favorable result quickly.”

Higgins is one of the most visible presences in college basketball. He has been reffing in the NCAA since 1988; today he calls around 90 games every season, and Higgins has been on the court for eight Final Four matchups and championship games in 2013 and 2016. He’s known for liberally using his whistle, including handing out technical fouls to coaches.

“We’re supposed to enforce the rules as written, right?” Higgins told Sports Illustrated in 2016. “The NCAA is always preaching sportsmanship, sportsmanship, sportsmanship. You can eat a little crow if you know you probably screwed a play up, but when you let coaches and players and coaches act like idiots, you lose all credibility. I try not to let it happen in my games, that’s for sure.”

In the offseason, the referee lives in Omaha, where he runs a roofing company called Weatherguard with his wife.

Those two worlds — offseason and in-season — collided after the Kentucky loss, the lawsuit argues.

“I do think the officiating the first half was putrid,” Jones told his Kentucky Sports Radio listeners. “And John Higgins has been part of some of Kentucky’s most painful losses.”

The day after the game, a video appeared online titled, “John Higgins Sabotage of Kentucky;” the clip featured footage from the game. Also, according to the lawsuit:

At the end of the Video, a photo of Mr. Higgins next to a Weatherguard truck appeared. Next to the photo were Weatherguard’s business phone number, its website address, and the Higgins family home phone number. Beneath the photo and contact information was the following: “Write a review of him here http:/www.facebook.com/rooferees.”

The same day, on Jones’s two-hour radio show, the host repeatedly brought up Higgins. He also read emails from callers proposing to leave negative Yelp reviews for Higgins’s business. While Jones “claimed that this was a bad thing to do, because it would constitute ‘harassment,'” the host continued to read emails from angry listeners.

In the following days, Jones again denied advocating for the online attacks on the business, but said that “it doesn’t mean it’s not funny,” the lawsuit says. Jones also stated, “You cannot blame this on KSR. . . . Well, maybe you can because I told you he was a roofer.”

The complaint argues: “In other words, while Mr. Jones claimed he did not ‘advocate’ such activity, any fan who wrote such a comment, outrageous enough, would be rewarded by having the comment read on the KSR show.”

Meanwhile, back in Omaha, Higgins and his family were enduring a monsoon of negative attention. Weatherguard was flooded with phone calls — 3,000 in the two days after the game, 75 percent of which came from Kentucky area codes, the complaint says. Online, the business was also swamped with one-star reviews on Google — 80 pans in a 24-hour period, none from Omaha. In total, 181 false reviews were submitted.

Trolls also put 700 angry comments on the business’s Facebook page, including:

John personally came out to fix my roof. I’ll say this guy was very professional. He clogged my toilet and didn’t tell anyone. I tried to get him to come back and finish my roof and he came back the next day showing up three hours late, smelling of tequila and strippers.

And:

Had this guy do my roofing. He came home from work, and he was getting it on with my wife. And he also stole my dog. I hate him.

The harassment also reached a scary stage, the lawsuit says. Hundreds of voice mails on the business’s phone and the Higgins’s line delivered death threats. “You’re gonna pay, buddy,” one said. “You enjoy your life before somebody kills you,” another stated.

Police eventually investigated a dozen that “rose to the level of an actual threat of death of bodily injury.” In total, Higgins says the harassment cost his business $75,000.

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