It's not quite that easy I'm afraid. Some libraries have put their microfilms online, but not all. Microfilms are by far the best way to look into anything predating 1990. In the 80's local news stayed local, it wasn't lambasted across the entire world like things are today. Sadly not all murders got the attention that would be given today.
The example you give is known because it's scandalous and unique, the kind of thing that will travel centuries. In old cases, it's far more common to be able to find information on a murderer than a murder victim. If a victim is known, it's usually because of the unusually heinous acts committed against them. As bad as this sounds, this murder is only average at best. No potential killer identified, no extreme acts committed against her, she was not famous. It's fairly forgettable in the terms of history.
Only recently have news agencies started keeping online articles up indefinitely. There's a period extending right up until very recently, that news would publish an online article and after so many months it would go to their archives. Not all news agencies kept those archives for longer than a year or two. Quite a few posts on this site have articles that can no longer be found because of this.