There are not 13,099 Illegal Immigrant Murders Roaming Free on American Streets
Or how you should learn to stop worrying and read the fine print
www.alexnowrasteh.com
I haven't heard the backstory on this, but it appears that they screaming about a bunch of murderers walking our streets.
Short version: They are "non-detained" by ICE. That doesn't mean they aren't detained by someone else. In jail. And some have served their sentences but can't be deported--realistically, you can't deport someone to a country that doesn't want them back.