The New York Times is reporting that the Justice Department is opening an antitrust investigation of Google’s settlement with authors and publishers over its Google Book Search service.

In 2005, the Authors Guild and the Association of American Publishers filed suit against Google, claiming that Google’s practice of scanning copyrighted books from libraries for use in its Book Search service was a violation of copyrights.

Google reached a settlement with the groups last October that gives Google the right to display the books online and to profit from them by selling access to individual texts, as well as selling subscriptions to its entire collection to libraries and other institutions, the Times reported, with revenue to be shared among Google, authors and publishers.

The problem is with books whose authors cannot be found or whose rights holders are unknown, because Google would have sole rights to those books, according to the Times. For its part, Google points out that users will now once again have access to many out-of-print books.