Dogberry, his men, and the sexton prepare to examine the prisoners Borachio and Conrade about their crime. The bumbling questioning by Dogberry first brings denials that Borachio and Conrade are "false knaves." The sexton asks that the witnesses be called to give their testimony on what they heard. George Seacoal, the watchman, gives his evidence, reporting Borachio's overheard statement to Conrade that Don John was a villain who had bribed him to accuse Hero falsely. Borachio does not deny this.
The sexton tells all of them that Don John has secretly gone away and that Hero has died. He instructs that the prisoners be brought to Leonato for judgment, and Conrade makes one final attempt to insult Dogberry, calling him "an ass," to which Dogberry takes great offense.
This brief scene makes Don John's treachery public, despite the clumsy examination by Dogberry and Verges. The prisoners first deny any wrongdoing when questioned by Dogberry, but after the specific evidence of watchman George Seacoal, their silence seems to be an admission of guilt. Conrade reacts with one final insult, to which Dogberry responds at some length, disappointed that the insult was not written into the testimony: "Oh, that I had been writ down an ass!"
One sign of Shakespeare's genius is his treatment of many secondary characters. Less skilled playwrights tend to give depth of character only to the primary characters, using the secondary characters to move the plot forward in some way, but without distinction among those secondary roles. Even with the relatively brief appearances of Borachio and Conrade, we catch glimpses of significant differences between their personalities and attitudes. Until this scene, Borachio appeared to be the more villainous of Don John's men: He first eavesdropped on Don Pedro and Claudio; he later proposed the window scene with Margaret; he relished his accomplishment to Conrade in the scene in which they were themselves overheard (note all the "noting" here). But when he learns of the disappearance of Don John (probably with his promised reward for the window scene) and of Hero's apparent death, he seems more subdued, not joining Conrade in the final insult of Dogberry. Furthermore, in the next scene, Borachio freely confesses and, in fact, regrets his actions, expects punishment, and exonerates Margaret.
In earlier scenes, we have seen differences between the personalities and attitudes of Ursula and Margaret. Even the men of the watch were shown to be different from one another in their first scene (Act III, Scene 3). In the present scene, their straightforward reports of few words solve the crime — in sharp contrast to the reports given by Dogberry and Verges. Ironically, the play's resolution rests on the testimony of two minor characters who have little to say — at least competently.