Good Question: Why Can't We Block Terror Groups From The Internet?

MINNEAPOLIS (WCCO) -- The FBI says the Orlando shooter was, in part, radicalized online.

Police say Omar Mateen called 911 during the attack and pledged allegiance to ISIS.

The shooting at the Pulse Night Club left 49 people dead and 53 hurt.

With ISIS and other terror groups using the web to spread their message, why can't we block terror groups from the Internet? Good Question.

"Last year alone, Twitter had about 46,000 social media accounts just for the Islamic State," said Peter Johnson.

Johnson is a former U.S. air marshal who now runs Archway Defense, which offers active shooter training for companies.

"People have tried to shut them down. They've shut down a couple hundred at a time, but you know Twitter, you just create a new alias," said Johnson.

Both Twitter and Facebook have become more active at deleting posts and blocking accounts of suspected terrorists -- to the point that their founders have become online ISIS targets. But it's not the only way terrorists communicate.

"Interpersonal communication can be encrypted through third party apps," said Johnson.

Apps, like Wickr, are encrypted making it hard to see who is talking to whom.

Johnson said the Dark Web is also hard to police. It's a collection of websites that hide IP addresses so you can't see who is behind the scenes.

Freedom of speech and censorship issues have come up when it comes to online policing. Though Johnson said people lose that right when lives are threatened.

"The problem is the speed in which social media works," he said. "You would need to employ literally an army of IT professionals to shut down these accounts on a daily basis. The only thing we can really do is attack the ideology."

Self-policing also plays a role in this. Users are encouraged to identify questionable content and alert web sites.

Johnson talked about attacking the ideology of radical Islam. What that means is getting help from the community in identifying those who are sending out terrorist propaganda.