Inspector Quine organizes a police lineup for Philip Dressler, the unwitting carrier of the heroin, in the hopes he can identify the porter who had grabbed his bag and flung it into Lefty Jenkins' cab.
Then ... The first group of porters who work for the steamship line that brought Dressler back to San Francisco file in for the lineup.
Then ... This view shows the whole front width of the room.
Then ... We get further clues from this view of the rear of the room.