Whom should the Prince pardon and whom should be punished?

At the end of Shakespeare's Romeo and Juliet, the Prince says:

"A gloomy peace this morning

The sun for sorrow will not show his head:

Go hence, to have more talk of these sad things;

Some shall be pardon'd and some punished:

For never was a story of more woe

Than this of Juliet and her Romeo." [Exits]

No specific answer is given. It is a rhetorical question. It is up to the reader of the story to come to their own conclusion(s), if any.