States vary in how they define criminal harassment. Generally, criminal harassment entails intentionally targeting someone else with behavior that is meant to alarm, annoy, torment or terrorize them. ... Harassment charges can range from misdemeanor to high level felony charges.
However, one would imagine if the target is known to be a government official in a non-political setting, particularly if her security detail advised leaving abruptly, the penalty would approach the higher end. Arguably, despite the hour, the Secretary may yet have been in the course of her duties.
It the police were called and no report filed it is likely a moot point. Of equal interest is whether such behavior by a DOJ employee will be tolerated even at a level far below the executive ranks.