After the series was discontinued in the US in 1991, Kosmos Verlag sought the rights to continue the series in Germany with German authors, and in 1994 signed a corresponding contract with Random House without the consent of Arthur's heirs. In 2002, Random House returned the rights of the ten volumes to Robert Arthur's heirs after the publisher failed to comply with the agreed republications of the works. In 1999, however, Kosmos-Verlag had already registered the word mark throughout Germany and by 2003 throughout Europe as well as a European trademark for audio carriers and printed products. Negotiations between Kosmos Verlag and the heirs on a new usage rights agreement failed because Kosmos relied on its trademark registration and ongoing agreements with Random House. Furthermore, Kosmos doubted that Arthur's heirs were the right holders since according to Arthur's will, all rights were to be transferred to the University of Michigan. At the end of 2004, Random House and Kosmos signed an extensive agreement to transfer all rights to the other American novels not written by Arthur to Kosmos Verlag. Due to the unclear legal situation, EUROPA decided at the beginning of 2005 not to publish any further episodes based on the book templates of Kosmos Verlag and discontinued the license payments to Kosmos. At that time the books “Spur ins Nichts” and “...und der Geisterzug” (both German only) had already been recorded as an radio play. In 2006, the parent company of the European label Sony Music Entertainment (formerly Sony BMG) finally gained all the German rights on Arthur's creations and the use of the original characters and showplaces independently from Kosmos publishing house of Robert Arthur's successors. The contract contained the right to order new books in German, as well as the right to evaluate the sound storage medium. Moreover, all were transferred: from "[...] interests [of Arthur's children] in all German audio recordings, bound books, pocketbooks, theatrical performances and electronic film recordings of theatrical performances to all existing derived products in Sony BMG". EUROPA developed a new audio book named "" based on it. Indeed, EUROPA avoided the use of the name "Die Drei ???" and also the name created by Kosmos because of the protection of the brand. Instead of that only characters and names which were based on Arthur's ideas were used (characters’ original names). The Kosmos publishing house continued its series of books under well-known titles and with famous character's names. The society filed a lawsuit against the Kosmos publishing house because Sony BMG itself saw its exploitation rights violated.