For decades, often using a fake identity, he stole antique maps worth thousands of dollars each. …
In July 2017, Schild, this time calling himself a history professor emeritus, visited the library of the University of Innsbruck, in the Austrian Alps. After he left, a librarian named Claudia Sojer plugged Schild’s name into a library newsletter and came across the warnings. She looked through the book Schild had studied—a 1627 volume by Johannes Kepler—and realized that an engraved world map, valued at €30,000, was missing. (She had been in the room with Schild, but had left briefly for a bathroom break.) Finally, prosecutors in Schild’s home district of Witten, near Bochum, managed to bring him in front of a court on charges of theft. …
Siehe https://www.atlasobscura.com/articles/how-german-librarians-caught-a-book-thief