| Includes a running list of characters who are known only by their last name. |
DC Universe[]
Batman[]
O'Hallihan was an adult male and a resident of Gotham City. He was a member of the Gotham City Police Department. O'Hallihan was one of the officers that brought Koyuki Nakano in for questioning following the murder of her husband, Gotham mayor Christopher Nakano. O'Hallihan was present in the interrogation room when detective Harvey Bullock asked Koyuki about her cell phone history. Oddly, Koyuki immediately lawyered up. (Batman Vol 3 154)