The difference is quite distinct, Justin was on Facebook. Facebook and LEO organizations have a cozy relationship, and Facebook provides all activity logs to LE

The difference is quite distinct, Justin was on Facebook. Facebook and LEO organizations have a cozy relationship, and Facebook provides all activity logs to LEO orgs for real-time processing. One of the Boston Bombers was a prolific Twitter poster, and I'm sure that factored in the decision to monitor Facebook activity in real-time.