Kurt Havelock faced six counts of mailing threatening communications in U.S. District Court in Phoenix.
Authorities alleged the 36-year-old Havelock bought an AR-15 semiautomatic rifle and 200 rounds of ammunition from the Scottsdale Gun Club on Jan. 30. The documents say Havelock wanted to kill people at the Feb. 3 Super Bowl in Glendale and was armed when he reached a parking lot near University of Phoenix Stadium where pregame activities were happening.
However, Havelock had a change of heart. He called his parents, and they persuaded him to turn himself in to Tempe police.
Havelock's father said his son was generally a good person who was being punished for momentarily snapping.
"I know what kind of kid he is. If he was a bad kid, I'd say, 'You deserved what you got.' But he's not," Frank Havelock said. "He needs to talk to a counselor. He doesn't need to be incarcerated."
Authorities said Havelock's threats caused people to fear for their safety.
"In today's society, violent threats against the public will be investigated to the fullest extent of the law," FBI Special Agent John Lewis said. "The guilty verdict of Kurt William Havelock shows that these types of threats will not be tolerated."
Havelock told the FBI he wanted to commit the slayings in retaliation for the Tempe City Council rejecting his liquor application for a restaurant he had recently opened.
In a manifesto mailed to various media outlets, Havelock vowed to "shed the blood of the innocent," according to court documents. "No one destroys my dream," he wrote.
Law enforcement intercepted the mailings before they reached the intended recipients.
Havelock will be sentenced Aug. 25. He faces a maximum sentence of five years in prison and a possible $250,000 fine.
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