Michael Bloomberg’s Democratic presidential campaign is trying to tie Sen. Bernie Sanders (I-Vt.) to the vandalism of its office in Knoxville, Tennessee, despite no evidence that he or one of his supporters was involved.

“This latest incident at our Knoxville campaign office is exactly what we’ve been warning about,” Bloomberg campaign manager Kevin Sheekey said in a statement. “We don’t know who is responsible for this vandalism, but we do know it echoes language from the Sanders campaign and its supporters.”

On Friday morning, a campaign volunteer arrived to find profanity spray painted across the front doors, along with handmade posters on the windows reading “Authoritarian,” “Classist” and “Oligarch.”

The campaign noted that in recent weeks, other offices have also been vandalized with similar messages, including in Toledo, Ohio; Youngstown, Ohio; Ann Arbor, Michigan; and Flint, Michigan.

Even though the Bloomberg campaign admits it doesn’t yet know who is behind the damage, it’s trying to blame Sanders and his supporters, even calling on the rival presidential contender to condemn what’s going on and implying he will be responsible if someone “gets hurt.”

“Over the past week, we’ve seen similar attacks against Mike Bloomberg 2020 offices in multiple states. Fortunately, no one has been injured. But this needs to end before someone gets hurt,” Sheekey said.

“We call on Bernie Sanders to immediately condemn these attacks and for his campaign to end the Trump-like rhetoric that is clearly encouraging his supporters to engage in behavior that has no place in our politics,” he added.

The Bloomberg campaign pointed to comments by Sanders and some of his aides, such as Sanders saying at a rally on Monday, “We are a democracy, not an oligarchy. You’re not going to buy this election.”

Sanders isn’t the only person, or even the only candidate, who has criticized Bloomberg along these lines.

But the senator has taken heat, including from other Democratic presidential candidates, for the vitriol that comes from some pockets of his supporters. At the candidate debate in Las Vegas this week, Sanders suggested that perhaps foreign forces were at work.

“All of us remember 2016, and what we remember is efforts by Russians and others to try to interfere in our elections and divide us up,” he said. “I’m not saying that’s happening, but it would not shock me.”

The Sanders campaigns did not immediately return a request for comment.