J.K. Rowling apologized on Twitter?

I head J.K. Rowling apologized on Twitter for killing off one of the characters in the story and her fans argued that.
I'm not interested in "Harry Potter" at all. But I have an interest in the author, if it means that the tweet could come from her consideration with awareness of the danger to put an end to the argument that had happened started and might not be likely to end.