Analysis of information sources in references of the Wikipedia article "Batman (Thomas Wayne)" in English language version.
[T]his film is inspired heavily by the classic Flashpoint storyline [which] saw The Flash break reality and go to a universe where Bruce Wayne died in Crime Alley which caused Thomas Wayne to become a murderous Batman and Martha Wayne to become a version of the Joker. However, the film replaces Thomas Wayne with [Michael] Keaton's iconic version of The Dark Knight.