Who killed Robin's parents?
Approved answer
The Tragic Fate of the Graysons
As the youngest member of the acrobatic troupe known as the Flying Graysons, Grayson witnesses a devastating event when Tony Zucco, a notorious mafia leader, murders his parents to extort money from their circus. After this tragic incident, Bruce Wayne adopts Grayson as his ward and begins training him to become his sidekick, Robin.