Herb Stork tells that (History and Prophecy: A Study in the Post-Exilic Period, House of Nabu, 1989, p. 150, n. 382):
Mordecai is remembered as having established an academy in Susa and being a scholar of some distinction. Louis Ginzberg. Legends of the Jews: volume 4. p. 383 and 445.
And, according to 2 Maccabees 2:
13 Nehemiah also narrated the same things in his writings and journals. He also told how, when Solomon established a library, he gathered the scrolls concerning the kings and prophets and the scrolls of David and letters of kings regarding offerings for solemn promises. 14 In the same way, Judas also gathered together all the scrolls that went missing because of the war, so that those documents are now in our possession. 15 So if you need them, send messengers to carry them back.