Mark Salter, longtime speechwriter for John McCain, has been revealed by several sources to Time as the anonymous author of "O" the novel, a fictional account of a 2012 presidential run that is supposedly loosely based off Obama's own presidential campaign.

In his 19 years on McCain's staff, Salter has collaborated with McCain on several nonfiction books and speeches. McCain apparently said he and Salter are "like brothers."

Also, it seems the definition of "in the room" is being used rather loosely in this case.

Sources aside, Time also mentions a couple of circumstantial clues that suggest Salter is the mystery author, including:

The "O" publisher Jonathan Karp (at Simon and Schuster) was Salter's editor on books he did with McCain.

(at Simon and Schuster) was Salter's editor on books he did with McCain. Salter's "non-denial denial was the closest to a confession of any suspect who was publicly asked."

There is a story early in the book that would have been known only to a McCain campaign insider such as Salter.

So whose name has now been cleared?

Stephen Colbert ran down the list on his show last night: "author of "Primary Colors" Joe Klein, White House Press Secretary Robert Gibbs, and even Rahm Emanuel (though if Rahm had written it, it would probably be called 'F')."

Publisher Karp even said, "Some people have suggested that it's Stephen Colbert..."

"I suppose it's possible," said Colbert, "I do have frequent episodes where I black out, though I've never woken up with a book before."

Finally, the insider speculation can end! Video below. The Wire even makes a cameo.