Yahoo News Explains: Social media's role in the age of mass shootings

A lone gunman walked into a synagogue in Pittsburgh and killed 11 people.

The alleged assailant, Robert D. Bowers, spewed hate speech on a social media site called Gab minutes before entering the Tree of Life Congregation.

The 46-year-old posted, “I can’t sit by and watch my people get slaughtered. Screw your optics, I’m going in.”

Gab has since been taken offline and removed from app stores, according to its website.

A statement on the Gab site said: “We have been smeared by the mainstream media for defending free expression and individual liberty for all people… Gab will continue to fight for the fundamental human right to speak freely.”

The issue has sparked a larger conversation about social media’s role in these attacks.

Earlier, Cesar Sayoc allegedly mailed pipe bombs to high-profile figures, including former President Barack Obama and actor Robert De Niro.

Related: Everything we know about the suspicious packages

Sayoc stuck to more traditional social media for his hate speech. On Twitter, he tweeted at former Vice President Joe Biden, former Attorney General Eric Holder, and many others.

One message read, “We will meet your threats right to your face soon.” Another to Holder said, “See U soon tick tock 4.”

He also threatened Rochelle Ritchie, a Democratic political commentator, on Twitter after she appeared on Fox News.

According to Ritchie, she reported the threat, but Twitter didn’t find any violation of its rules.

Both Sayoc and Bowers used their accounts to talk about President Trump. While Sayoc praised the president, Bowers criticized him for surrounding himself with Jews.

One study by the Anti-Defamation League found that hate speech toward Jews has spiked leading up to the midterm elections.

Three million users posted or reposted anti-Semitic content over a 12-month period in 2017 on Twitter.

The day before Nikolas Cruz opened fire on 17 people at a Florida high school, he reportedly posted a comment on YouTube: “Im going to be a professional school shooter.”

Companies have taken steps to curb hate speech. Facebook set up a “War Room” to combat trolls and fake accounts leading up to the midterm elections.

YouTube allows users to flag inappropriate content and comments. In three months, YouTube says it took down 8 million videos containing adult content or spam. Eight percent of videos removed for violent extremism were taken down with fewer than 10 views.

Similarly, Twitter reportedly hired academics to help combat “intolerant discourse” on its site.

President Trump tweeted after the synagogue shooting, encouraging people to unite.

A day later, he posted about “the fake news.”

With social media’s presence only growing in our society, it’s clear the problem of fake news and hate speech isn’t going away.

Read more from Yahoo News: