Now that this has been deemed a "terrorist attack", doesn't this fall under the jurisdiction of the military justice? Irrespective if the guilty party or parti

Now that this has been deemed a "terrorist attack", doesn't this fall under the jurisdiction of the military justice? Irrespective if the guilty party or parties are US citizens or foreign nationals - or I suppose even if they are just suspects or persons of interest - can't they be detained indefinitely without trial? Or even worse US citizen or not, suspects, without trial, can be added to the Kill List. Kind of scary, especially with the internet creating suspects for the government.