Where should they be detained and for how long?  I'm sure the jails are already overcrowded.  If the feds want localities to hold their suspected violators, then they should build facilities for that.  But people are so easily fooled.  Deporting someone serves no useful purpose.  Those who commit crimes, simply return to re-offend, and have on may occasions, which proves deportation doesn't work.  It's a waste of time and money.