A North Shore woman is recovering from knife wounds, and the boyfriend whom authorities say inflicted them is dead after the intervention of a neighbor, who shot the assailant dead.
So what does the law say about using deadly force when in defense of someone other than oneself?
Loyola law professor Dane Ciolino says it is basically the same standard as when one's own life is in danger: "If it's reasonably apparent that the person being attacked could have used such force themselves, justifiably."
So even if it's not strictly defense of oneself, a citizen is justified in taking someone's life to save another life.
"It's essentially still viewed from the eyes of the victim of the attack," Ciolino explained. "If that person could have used defensive force, so to can a third person trying to protect the victim."
The coroner's office identified the deceased as 49-year-old Shawn Quinn. The sheriff's office has not filed charges.