PHOENIX — Legal advocacy groups that opposed former Sheriff Joe Arpaio’s pardon are asking an appeals court to appoint a special prosecutor to appeal a lower-court decision that let the retired lawman’s clemency stand.

The groups filed a brief last week with the 9th Circuit Court of Appeals saying a special prosecutor should be appointed because the U.S. Justice Department isn’t pursuing an appeal and the power of the courts is at stake.

The pardon spared Arpaio a possible jail sentence for his contempt of court conviction for intentionally disobeying a 2011 court order to stop his traffic patrols that targeted immigrants.

The case has since been dismissed, but the judge who found Arpaio guilty has said the pardon hasn’t erased the conviction from his record.