killer confirmation

"RELEASE" Season 9, Episode 17
Who was the killer?
I am guessing that the indictment that Regali was paying off to Follmer to cover up for him was since he knew the suspect Harvey from prison time, he was placed in the area at the time of the murder through a credit card gas receipt. There was a witness to the pay-off and the incident was caught on video tape which Regali held over Follmer as blackmail. Barbara did not recognize Regali in the line-up because she just did not see him, but why did she seem to recognize Hayes/Mimms who also was in the area at the time of the murder?