How did the husband die?
In "A Jury of Her Peers," Minnie's husband dies of strangulation. His wife tells the police that someone sneaked into the house, placed a rope around her husband's neck, and strangled him while he was sleeping. That's the wife's version.
The implication is that Minnie strangled her husband herself. The two women who make up the "jury of her peers," discover evidence that suggests Minnie killed her husband the same way her husband killed her canary. Minnie, trapped in a subservient position to her husband and isolated from the outside world--she doesn't even have a telephone--apparently found consolation and comfort in the singing of the canary. The suggestion is that when the husband killed the bird, Minnie killed him.