Several emails show Walker suggesting minor changes to press releases, writing his own responses, and pushing back against news stories he did not view as favorable. In an April 1, 2010, email sent to his chief of staff Tom Nardelli, Walker outlines his media strategy and tells Nardelli: "No one should be commenting on anything until we have a chance to talk and until we agree on our message." In another email string two weeks later, Walker, his campaign staff and his county staff try to quickly react to questions about why he wasn't doing public service announcements about donating blood. Even though the emails come from personal computers of county workers, any material dubbed to be non-public, such as private employee information, personal medical information and attorney-client communication, was removed. A John Doe investigation is Wisconsin's version of a grand jury probe where information is tightly controlled and investigators go about their work in secret. A second investigation began in 2012 and focused on alleged illegal coordination between Walker's recall campaign and more than two dozen conservative groups.