We were wrong
The woman, according to police, had killed her husband. It's a homicide, not yet a murder, which is a legal distinction. A prosecutor can charge one with murder, and it up to a jury (or a judge or a defendant, if they plead guilty or no contest) to determine if it is murder.
Funny thing, though, is I still think of these cases, really these tragedies, as murder-suicides. I can't find a better term. Murder-suicide just flows. I'd call it a murder-suicide, but I would not say that the woman murdered her husband.