All eyes were on 20-year-old Abdullahi Yusuf when he stepped on the stand in federal court last week in Minneapolis to testify for the prosecution in America's largest ISIS recruitment trial.
As Yusuf began to speak, his words provided a rare, behind-the-scenes look at how more than a dozen young men convinced themselves that the way to prove they were good Muslims was to travel to Syria and fight for ISIS.
The radicalization process in this case was frightening simple. It began with a meal at a Somali restaurant and a pickup game of basketball.