A fight between Fortress Investment Group LLC and Erich Spangenberg over the transfer of a single patent already in active litigation has broken out, first into federal court and now into New York state court. The patent is one among many relinquished by Marathon Patent Group, Inc. to Fortress last year after the NPE failed to repay Fortress $15.99M in debt financing. Rensselaer Polytechnic Institute (RPI) developed the patent, which a Fortress entity is currently asserting against Amazon; the patent was also the subject of litigation against Apple that ended in a reported $24.9M settlement in 2016. Court filings in connection with the dispute between Fortress and Spangenberg shed light on the millions of dollars at stake in the monetization of patents that Marathon was forced to hand over.