Possible Duplicate:
Punctuation of direct speech, edge cases
Space before three dots?
"I don't think so," she stated.
"I don't think..." her voice trailed off.
Is this second sentence correct from punctuation point of view (ellipsis working along with the same rule as ?,! - replacing the comma), or does it require an extra comma? (or yet something different?)
I'm aware it is normally used instead of a comma or a full stop, with very rare exceptions, but the rules of using punctuation at the end of interrupted quotes still baffle me.