Black Racer who Bart revealed has been following him since Lex tortured him in "Absolute Justice" I believe.
Actually, the sixth season ep in which Lex tortured Bart was simply called 'Justice', which basically introduced the JL. Not to be confused with the two part 'Absolute Justice'.
Finally got the Comixology app up and running on my wife's S-Tab (with many thanks to Mike Farley
for his assistance!) I'm looking forward to catching up on the last four issues on the Sony; much easier than lugging my laptop into bed!