Justice League: A Better World
George “Digger” Harkness
George “Digger” Harkness is a violent thug from Australia who uses a variety of high-tech boomerangs to commit crimes and fight the Flash. This has made him a member of the violent Rogues gallery. He has also been a member of the Suicide Squad, the Injustice Society, and the Secret Society of Super-Villains . His son is Owen Mercer, a character of conflicted morality with limited super-speed.
Geaorge Harkness was an enemy of the Flash and a member of the Central City Rogue Gallery, Captain Boomerang took the Justice Lords advice and retired in late 1996. Captain Boomerang was very crafty using his Captain Boomerangs Gadgets. He’s currently living in Australia and working as a guide.
DC Wikia Entry