When asked about a lawyer, a suspect mentions Perry Mason, a TV lawyer played by actor Raymond Burr. Dietrich says "I think he retired.", to which the suspect replies "Yes, probably after the accident." That is an inside joke referring to the fact that Raymond Burr had moved on to play the wheelchair-bound eponymous detective in the TV series "Ironside (1967)", which began the year after "Perry Mason" ended.
The name of this episode is odd considering it's the next episode in which Nick's desk is addressed.
The theme music played after the final freeze frame is sped up.