Why haven't we heard about other suspects in the Newtown shooting?

I was blindsided this evening when I stumbled across this youtube video (warning, this woman curses like a sailor)

[video removed]

Which links to this article: Sandy Hook DA cites 'potential suspects,' fears witness safety

I was under the impression that the official story is that Adam Lanza was a loner, and the lone gunman of this crime. Now, the Connecticut State Attorney is, in this article, that there are multiple suspects. Additionally, those suspects are being kept confidential to protect them.

I understand keeping them protected, because they might be innocent - and if their names are out there, it's possible (probable) that a vigilante might just take them out. But keeping the information that there are other suspects would indicate that they believe there were multiple shooters.

Why haven't we seen this in the media? Instead, we're seeing the same old "lone gunman" line.