Executioner (S18E09)

Dr. Mark Burns (guest star Alan Zweibel) is found murdered in his hotel room while attending an out-of-town convention. Detectives Lupo (Jeremy Sisto) and Green (Jesse L. Martin) learn that Dr. Burns made a large withdrawal from his bank account moments before he was murdered. Evidence rules out the con artists who scammed Burns as suspects, but a hotel surveillance tape shows a man with a southern accent vehemently knocking on the door looking for a different physician, Dr. Garrison (guest star James Rebhorn). This finding leads the detectives to believe Dr. Garrison may have been the intended target and his life is still at risk. (iTunes)