In the days since the shooting at Pulse night club in Orlando, Florida, the investigation has turned to the gunman, Omar Mateen.

He allegedly claimed allegiance to ISIS in a 911 call from the club. The shooter had previously been interviewed by the FBI for possible ties to extremist organizations, but authorities found no evidence he posed a threat.

The topic now is homegrown extremism and self-radicalization: What does it mean, and how can it be confronted?

Seamus Hughes is the deputy director of the Program on Extremism at George Washington University. He joined the show to explain more about the process of self-radicalizing, and what factors have changed that process.

To listen to the full interview, click on the blue audio player above.