Early on in Batman v Superman, Batman stares solemnly at a tattered Robin suit, a moment director Zack Snyder uses to explain a pivotal moment in Batman’s history. And while we always assumed it was Joker who was responsible for the suit’s worn appearance, we now have confirmation.

Speaking with IGN, Snyder revealed the history behind the moment.

In my mind, it was that Robin had died about 10 years earlier in some run in with a young Joker. So that was an interesting thing to me. Sorta a fun backstory to play with. I felt like there had been loss and there had been sacrifice.

In the comics, “A Death in the Family” remains one of the darker story arcs in the DC universe, and it sounds like that’s where Snyder is finding his inspiration. It’s a sobering moment in a movie that’s already pretty bleak, but great because it explains why this version of Batman is so angry and road weary.

Not only does it provide audiences with some important backstory, but it suggests Joker is not Robin, as some fan theories had guessed. However, it doesn’t rule out the possibility of Robin becoming Red Hood even though Snyder claims Robin is dead.

Whether or not we’ll ever see this moment play out on screen remains to be seen. Ben Affleck has reportedly written a script for a standalone Batman flick, so perhaps there will come a day when we learn more about Robin’s run-in with the Joker.