No evidence means no arrest, even if a possible terrorist is on authorities' radar

The World
French Police forces take part in a mock terrorist attack drill at a "fan zone" at the Place des Quinconces in Bordeaux, southwestern France, in preparation of security measures for the UEFA 2016 European Championship, April 4, 2016.

French Police forces take part in a mock terrorist attack drill at a "fan zone" at the Place des Quinconces in Bordeaux, southwestern France, in preparation of security measures for the UEFA 2016 European Championship, April 4, 2016.

REUTERS/Georges Gobet

How do you prosecute a thought? It's something law enforcement authorities are struggling with right now. When does a violent thought become a crime?

Both Omar Mateen, the Orlando shooter, and Larossi Abballa, the man who knifed a couple in France and left them to die, were known to authorities. The problem was, they had only expressed alarming thoughts. The authorities didn't have enough concrete evidence to make arrests.

Rukmini Callimachi, reporter for the New York Times recently wrote about this.

“Often, the only bread crumbs that these suspects leave is in the form of a violent thought that is expressed through speech,” says Callimachi. “And when you’re in a legal system which respects civil and personal liberties, it becomes very hard for prosecutors to argue that somebody making a violent statement on Facebook is really going to take the next step and kill somebody.”

Read her full story.