8 Mysteries Even Batman Couldn't Solve
4. The Death Of The Flying Graysons - Long Shadows
Following the events of Final Crisis, Bruce Wayne was dead (see: sent back in time). With Gotham City in need of someone to take over the cape 'n' cowl, it would be Dick Grayson who would eventually take on the Batman moniker.
In one of the earliest stories of this time as the Caped Crusader, Batman #691's Long Shadows sees Dick battle Two-Face in the Batcave. Once that fight's out of the way, Grayson and Alfred decide to strip back the cave and have somewhat of a tidy-up of the place. It's here, though, that this new Batman finds a USB drive that throws the established canon up in the air.
For the majority of the character's published lifespan, the parents of Dick Grayson were murdered as part of a Tony Zucco-organised hit - at times with a sprinkling of Two-Face thrown in, too - yet Batman #691 suggested there was more to the death of John and and Mary Grayson.
With that issue's final few panels, Dick inspects a USB drive found hidden in the base of the case holding Jason Todd's old Robin suit. There, he finds that Bruce had previously been working on the old Flying Graysons case, for Wayne felt he hadn't managed to fully unearth the truth about those murders.
Unfortunately for readers, much like Dick, we never got an answer to this, as the subject was bizarrely never touched upon again.