Seconds after Sanders took the stage, a dozen protesters from the city's Black Lives Matter chapter jumped barricades around the stage and grabbed the microphone from the senator. Holding a banner that said "Smash Racism," two of the protesters -- Marissa Janae Johnson and Mara Jacqeline Willaford, the co-founders of the chapter -- began to address the crowd.
"My name is Marissa Janae Johnson, co-founder of Black Lives Matter Seattle," she said to sustained boos for an audience that had waited an hour and a half to hear Sanders. "I was going to tell Bernie how racist this city is, filled with its progressives, but you already did it for me, thank you.
"You are never going to hear Bernie speak if I don't hear silence now," said Johnson, adding later, "Now that you've covered yourself in your white supremacist liberalism, I will formally welcome Bernie Sanders to Seattle."
To sustained boos from the audience that assembled to see Sanders, Johnson demanded that the senator take action on saving black lives and called on him to release his plans to reform policing.
"Bernie Sanders, would you please come over here," she said.
Johnson and Willaford demanded -- and eventually won -- a four-and-a-half-minute-long moment of silence in honor of Michael Brown, the unarmed black teenager who was killed by an officer in Ferguson, Missouri, a year ago on Sunday.
Sanders stood just feet away off stage, chatting with his wife, Jane, and the three aides that came to Seattle with him. Sanders' aides said the senator had no plans of leaving during the protests, but once Johnson did not appear willing to give up the mic after the moment of silence, organizers effectively shut down the event.
"I think it is unfortunate because, among other things, I wanted to talk about the issues of black lives, the fact that the American people are tired of seeing unarmed African-Americans shot and killed," Sanders told CNN after the event. "But there are other issues as well that we have to talk about, and that is the fact that the middle class of this country is disappearing and most importantly, we don't bring change in this country... unless all people stand together. That is what we have to do."
Sanders never addressed the crowd. After the event was ended, he waved at his supporters from the stage and then made his way through the crowd, shaking hands and taking pictures with people that came to see him speak.
"We need to hear your message," said one man as Sanders walked through the crowd.
"Come tonight," Sanders said, referencing his large rally Saturday night at the University of Washington.
Others said, "We love you, Bernie," and thanked him for coming.
"Don't forget about black lives," one man said in the crowd. Sanders' wife responded: "He's not."
When CNN asked about the protesters wanting to hear his criminal justice message, Sanders said, "They didn't want to hear anything."
In a statement to CNN after the event, Seattle's Black Lives Matter chapter said it protested the event because "the problem with Sanders, and with white Seattle progressives in general, is that they are utterly and totally useless (when not outright harmful) in terms of the fight for Black lives."
The statement added: "White progressive Seattle and Bernie Sanders cannot call themselves liberals while they participate in the racist system that claims Black lives."
This is not the first time Sanders has been confronted by Black Lives Matters protesters. At a liberal gathering in Arizona last month, the liberal senator was confronted by similar protests
"Black lives, of course, matter. I spent 50 years of my life fighting for civil rights and for dignity," he said then. "But if you don't want me to be here, that's OK. I don't want to out-scream people."
Sanders has started to address race issues more than he did at the start of his campaign, but he still regularly frames issues of race and inequality as economic matters, arguing that the key to combating racial disparities is by raising wages and increasing opportunities.