The estate of Arthur Conan Doyle asked a seemingly unsympathetic Seventh Circuit on Thursday to overturn a lower-court ruling that the elements from the first 50 Sherlock Holmes stories have lapsed into the public domain in the United States.

According to Law 360, estate attorney Benjamin Allison insisted that U.S. District Judge Ruben Castillo erred in December 2013 when he rejected the novel argument that the characters were effectively incomplete until the author’s final Holmes story was published in the United States, leaving the work protected by copyright. Castillo instead determined that all but the 10 short stories published after Jan. 1, 1923 are now part of the public domain, permitting writers and artists to use a majority of the characters and elements without paying a licensing fee to the Doyle estate.

The Seventh Circuit's three-judge panel appeared no more enamored with Allison's argument than Castillo did, with U.S. Circuit Judge Richard Posner characterizing the estate's position as a “very aggressive attempt to enlarge copyright law.” He said if the appeals court were to accept the estate's position, it would create an “irresistible temptation” for copyright holders to keep creating variations of early works simply to keep them out of the public domain.

The case involves Leslie Klinger, who served as an adviser on director Guy Ritchie’s two Sherlock Holmes films and with Laurie R. King edited In the Company of Sherlock Holmes, a collection of new stories written by different authors. The two had paid a $5,000 licensing fee for a previous Holmes-inspired collection, but their publisher decided not to move forward with In the Company of Sherlock Holmes after receiving a letter from the Doyle estate threatening to block sales of the book through Amazon, Barnes & Noble and other retailers unless it was paid another fee. In response, Klinger sued the estate.

On Thursday, Klinger's attorney Jonathan Kirsch accused the Doyle estate of using a "bullying tactic" and creating a “fog of uncertainty” around the character rights so it can extract licensing fees. Posner echoed that opinion, telling Allison, “It becomes clear that what you’re trying to do is just tie everybody in knots who is trying to write a Sherlock Holmes story so you can get your licensing fee."

Law360 notes that even if the Doyle estate were to lose its copyright argument, it still controls the trademarks, which would harpoon any efforts to market and merchandise an "unsanctioned" Holmes project. However, that position raised a few eyebrows when it was floated by Allison in January.

“There is a very good reason why the Estate did not assert trademark protection: The Estate does not own any trademarks," Klinger said at the time. “They have applied for them, and there will be substantial opposition."

The copyright of Doyle's Sherlock Holmes works expired in 1980 in the United Kingdom. His 10 post-1922 stories enter the public domain in 2022 in the United States.