The bipartisan leaders of the House Homeland Security Committee on Tuesday sent to a letter to Jim Watkins, owner and operator of the anonymous forum 8chan, asking him to testify about his efforts to "investigate and mitigate the proliferation of extremist content" on his website.

Why it matters: The letter notes that there have been at least three acts of white supremacist violence linked to 8chan this year, including the mass shooting in El Paso this weekend. On Monday, 8chan's network service operator Cloudflare called the website a "cesspool of hate" before shutting down its services. The founder of 8chan has also called for the site to be shut down, labeling it a "receptive audience for domestic terrorists" after the suspected El Paso terrorist posted an anti-immigrant manifesto on 8chan's message board hours before opening fire.

Go deeper: What to do about 8chan, the net's atrocity megaphone