The controversial “Free Speech Week” at the University of California, Berkeley has ended prematurely as student organizers signal a potential lawsuit against the school.

On Sunday, conservative provocateur Milo Yiannopoulos attempted to follow through on his promise to speak at Berkeley despite the decision of the Berkeley Patriot, a student organization that had agreed to sponsor the Free Speech Week, to pull its support from the 4-day event, citing pressure from the university.

"Despite the machinations of every component of the Berkeley and UC Berkeley administration, we showed up."

[RELATED: ‘Free Speech Week’ still on despite sponsor exit]

In a letter to Berkeley’s Interim Vice Chancellor Stephen Sutton posted online by Yiannopoulos, the attorneys representing the Berkeley Patriot threatened legal action against the university for allegedly failing “to protect our students from physical assault and vandalism,” threatening students with a “hate crime” investigation, and several other grievances.

“The intent of the threat was clear: Cease speaking out or face criminal investigation,” the attorneys wrote. “Well, our clients’ heard the Chancellor’s threat. They will be quiet, for now.”

“You are further notified that our clients are contemplating initiating litigation against the responsible parties and the administration for violation of our clients civil rights,” the attorneys also warned.

The Berkeley Patriot’s decision to withdraw from the event meant that Yiannopoulos no longer had an official venue for the speakers, a complication that ultimately sidelined the event on Sunday.

In an Instagram post following his short speech on campus, Yiannopoulos also accused the Berkeley police of blocking entrance to his unofficial appearance and asking for tickets even though “it wasn't a ticketed event.”

“HUNDREDS of people were waiting to get in. The press wasn't showing the lines outside and instead kept asking why no one had shown up when there were about 500 people waiting to get in,” Yiannopoulos wrote.

“The vast majority of the crowd was still waiting outside, being held by police, when I spoke,” he added. “The entire Berkeley College Republican group was refused entry. The police even had a device that was nuking our drone signal.”

[RELATED: Berkeley Chancellor vows to ensure free speech on campus]

Yiannopoulos further explained that he was “denied any amplified sound whatsoever” and noted that the police “refused to remove screeching protesters who made it impossible to deliver any speeches.”

“Despite the machinations of every component of the Berkeley and UC Berkeley administration, we showed up. We will keep showing up. See you back in Berkeley next year!”

According to The Mercury News, Yiannopoulos’ 15 minute speech on Sunday cost the university approximately $800,000.

[RELATED: UC system to chip in $300K for ‘Free Speech Week’ security]

Shortly before the controversial event, UC Berkeley spokesperson Dan Mogulof announced that Free Speech Week was cancelled but reiterated that the school continues to support free speech.

“We want to send the strongest possible message that we will continue to work constructively with campus organizations to host their speakers on our campus,” Mogulof said in an email to The Daily Californian. “We will in the future, as we have in the past, go to great lengths to support their rights and provide security for their events.”

Mogulof also told the publication that “claims made by external parties that the University sought to place the speakers in harm’s way are unfortunate,” adding that the administration was “confident that UCPD would have had the necessary resources in place to provide security for the events.”

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