BERKELEY (CBS SF) — Four people injured during a riot that forced a speech by right-wing provocateur Milo Yiannopoulos to be cancelled at UC Berkeley last year are suing the university, the city of Berkeley and two former UC employees.

In the suit filed late last week, the four claim the parties failed to protect from being pepper-sprayed and assaulted.

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Attorney Shawn Steel says his clients had no idea that violence was going to break out before the Feb. 1, 2017 event. But believes police should have known and did not do enough to protect them.

“They’re specialists (the campus and city police). They understand criminal behavior,” Steel said. “They’ve had riots in Berkeley before … but I think theccivilian authority – this is what we’re going to have to prove – basically told the professionals ‘Stand down, We don’t want no trouble.'”

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Three of the plaintiffs — John Jennings, Katrina Redelsheimer and Trever Hatch — are from San Francisco and were trying to attend the Yiannopoulous event and were assaulted in Sproul Plaza. An Oakland man — Donald Fletcher — was at an off-campus bar when he learned that the event was canceled, but then entered the fray and was injured.

The suit claims that half a dozen masked rioters attacked Jennings and Redelsheimer with sticks and pepper spray, leaving them with concussions, broken or bruised ribs, cuts and burns.

Fletcher, according to the suit, spent the night at Highland Hospital after being beaten unconscious on Bancroft Avenue.

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The plaintiffs are seeking unspecified damages. A University spokesman told KPIX 5 that administrators have not seen the lawsuit, so they have no comment.