What makes a local story a national one?

The murder of Yale medical student Amie Le would seem to be a local story, not a national one. Yet her death has carried the networks, major cable news networks, and online sites for several days.

Why? What made a single murder a national news story in the minds of producers and editors at major outlets?

Was it because it was at Yale, one of the country's top universities and located in a major media market? If a death like this would have happened at, say, the University of Kansas medical school, would it have received the same attention?

Was it because Le was a doctoral student with a promising future? Was it because her body was discovered on the day of her planned wedding day?

It would be an interesting case study for a journalism class. What you learn in this business is there's no set formula for what determines how big a story is or is not. What it usually comes down to is what an editor decides, and that is often subjective.