I liked how they got all the witnesses together to discuss the case, but he just put up one of his grids and with various cross references (who was with who, who saw who and where etc.) and in a quick process of elimination he said "Well, it was suspect B" and as they all looked at her she burst out crying and admitted the murder, so in a matter of minutes he had a solved a case that looked like it was going to drag on in a usual police investigation, leaving everyone stunned.
Also, what I think will come up again, is the smoking female detective in the car park suspiciously wondering why he didn't seem to be able to drive his own car properly.