doubts about mvc in codeigniter

[eluser]Unknown[/eluser]
I'm doing a news site, and I wan't to do a comments part in each news, in the same page, but I don't know how to do.

I have my controller news, where my method index is a list of news and the method detail I pass the id and return the news.

I know how to do this in a separated controller just like the videotutorial of the blog that is in the codeigniter site.

I need to create a new controller comments? How can I put the comments and the comments form, in the same page of the news?