On Monday, former New York Mayor Michael Bloomberg criticized Bernie Sanders.
Bloomberg posted an online video calling Sanders supporters aggressive.
The video featuring violent and derogatory tweets, memes and videos purportedly posted by Sanders online supporters.
The video end with a clip of Sanders calling for people "who hold different views" to "engage in a civil discourse."
Text then flashes on-screen, asking, "Really?"
The behavior of many of Sanders online supporters has fueled a backlash from Sanders opponents.