Joking aside, if activists committed any crime, you follow the legal procedures and challenge them in a court of law before a judge and let the defendants present their case in a free trial and see if any of the charges you brought against them sticks, otherwise shut up and leave them alone because if you start allowing police to hand out sentences without legal recourse to challenge these arbitrary punishments, you'll descend slowly into a police state and horrific society to live within.
First, it wasn't a joke. Second, we were discussing putting environment activists under arbitrary house arrest not terrorists or terrorism. Your anger at the tragic death should be directed at the terrorists or the security apparatus which failed miserably to protect people in the "west" and not at me or the activists.
Try next time to read the comments first before jumping into the discussion.
You have to get a verdict first in order to detain them and not let them do the job for you and make them go through hardships for a redress and emergency laws are not just or fair to entertain them .
Like those pesky ecologists that endanger the state by stopping economic growth and slowing down job creation at the cost of increased pollution, right?
People who commit crimes should be fined or arrested. These are preventive house arrests for crimes that they might commit in the future. You really don't see the problem with this?
By and large its not clear ISIS actually wants people to commit terror attacks in the west since it gets potentially useful recruits killed not fighting for territory in the middle East (note they are big on how you should definitely move to the ISIS territories).