Exculpate is typically defined as something that attempts to justify a possibly wrong action.
To clear of guilt or blame.
Duhaime Legal Dictionary
Something that excuses or justifies a wrong action.
To clear from alleged fault or guilt.
Lect Law Library
"To exculpate" means to free a particular individual from culpability after he or she has caused loss or damage and to represent this in a judgment that is either an acquittal or mitigates sentencing in the criminal law, or reduces or extinguishes the liability to pay compensation to the victim in the civil law.