The old criminal Riddler is gone. Before you stands Edward Nigma, a man reborn. My doctors say my formerly abberant ways have been permanently dispelled, leaving intact my, if I may say so, brilliant analytical mind. 
Detective Comics #822 is an issue of the series Detective Comics (Volume 1) with a cover date of October, 2006. It was published on August 2, 2006.
Synopsis for "E. Nigma, Consulting Detective"
Batman returns to the Batcave after capturing Roxy Rocket. He has to go upstairs to confront The Riddler, now reformed and a private investigator, who has come to acquit Bruce Wayne of Karrie Bishop's murder. It isn't him in the photo with Bishop, taken on the day of her death, but someone impersonating him. He has brought a camera crew with him.
Commissioner Gordon explains to Bruce that the Riddler was given a clean bill of health by Arkham Asylum after Bishop's uncle Sherman bribed the asylum because he wanted a genius to investigate his niece's murder.
Batman and the Riddler's investigation takes them both to Pandora's Box, a BDSM club frequented by Bishop's on-and-off boyfriend Greg Lanner. Lanner's alibi is called into question, and when they track him down, they find him dead with a suicide note confessing to just the scenario the Riddler worked out. While the Riddler calls Bishop's uncle, Batman follows a trail of bloody footprints out of the room.
Batman goes to confront Derek Lewis, the celebrity impersonator who was photographed with Bishop. Lewis's testimony leads Batman to Sarah Morton, Sherman Bishop's personal assistant. She killed Bishop so she could loot Bishop's trust fund while her uncle was grieving, and then killed Lanner and falsified his confession. Morton is arrested by Gordon.
Appearing in "E. Nigma, Consulting Detective"
Featured Characters:
Supporting Characters:
- Alfred Pennyworth
- James Gordon
- The Riddler (reforms)
Antagonists:
- Roxy Rocket
- Sarah Morton (Single appearance)
Other Characters:
- Derek Lewis (Single appearance)
- Greg Lanner (Single appearance; dies)
- Karrie Bishop (Deceased)
- Mabel Martin (First appearance)
- Pandora (Single appearance)
- Sherman Bishop (Behind the scenes)
- Zeke the Bartender (Single appearance)
Locations:
- Gotham City
- Batcave
- Pandora's Box
- The Treasure Chest
- Wayne Manor
Items:
Vehicles:
Notes
- This issue is reprinted in:
- Don Kramer's run as penciler on Detective Comics begins with this issue.