Spider Conway
Spider Conway was a two-bit criminal who once worked for Rupert Thorne. He also worked closely with Killer Croc for a time, until Croc was busted by Detective Harvey Bullock and Conway's testimony put Croc behind bars. Conway lied at a graft inquest years later and said that Bullock was taking bribes from Thorne, but was found guilty of perjury and sent to prison.
An unspecified amount of time later, Conway made a deal with the Gotham police department to testify against Rupert Thorne, but he was abducted by a newly-escaped Killer Croc en route tot he courthouse, as part of Croc's plan to get revenge against Bullock (by making it look like Bullock had kidnapped Conway).
Conway was held captive by Croc in his underwater cave lair along with Joey the Snail, until they were both rescued by Batman. Once again, Conway's testimony was used to help Bullock and put Killer Croc back in jail again.