J.K. Rowling has set a release date for her new "Cormoran Strike" book. The 52-year-old British author, born Joanne Rowling, will publish the novel "Lethal White" on Sept. 18 under the pen name Robert Galbraith. Rowling shared the news Tuesday on the official Robert Galbraith Twitter account. She included a photo of the book's cover. "Lethal White, the fourth installment in the Strike novels, will be out on 18 September and is available now to pre-order, and this is what it will look like #LethalWhite #Strike," the author wrote. Rowling uses the pseudonym J.K. Rowling for her "Harry Potter" books and Robert Galbraith for the "Cormoran Strike" novels. "Lethal White" follows "The Cuckoo's Calling" (2013), "The Silkworm" (2014) and "Career of Evil (2015)." "Lethal White" will follow Strike, a private investigator, as he takes on a new case from a troubled young man, according to Entertainment Weekly. The man, Billy, asks Strike to look into a crime he thinks he witnessed as a child.