Google disabled its author search functionality from Google News in favor of the Google+ Authorship capabilities it introduced in November, according to Search Engine Land. Searching within Google News for "author:‘firstname lastname,'" returns no documents, but participating journalists can opt to have a link to their Google+ profiles displayed next to articles they've written that appear on Google News. Readers can then click to add the author to their circles.
A query about this change, along with Google's response, can be found here. Google says that the Authorship links, which previously only provided a hyperlink to search for other stories by the same author, are now integrated with Google+ to facilitate "following and engagement between authors and readers."
The Google News blog explains the Authorship/Google+ integration further in this post.