Similar to post-conviction, Coram Nobis proceedings challenge the validity of a prior criminal conviction.  However, unlike post-conviction, these proceedings strictly pertain to defendants who have already completed the sentence in question, yet are suffering collateral consequences from the conviction.  These consequences may be in the form of deportation proceedings or the prior conviction serving as a predicate for a subsequent offender enhancement:

State v. Maxim Emfremov.  Convictions arising from two guilty pleas in the District Court for Baltimore City were vacated.  Mr. Emfremov released from the custody of the Department of Homeland Security pending final hearing on deportation proceedings.