City News Service says 42-year-old Yvonne Robinson remains free on bail ahead of a Feb. 27 court appearance.
Also charged is Prentice Jones, the 24-year-old brother of Robinson's brother-in-law, who also pleaded not guilty.
Prosecutors say Robinson, a 13-year veteran who last worked as a juvenile division detective, leaked information to the Baby Insane Crips, who counted Jones among their members.
Detectives investigating the 2009 killing of a 19-year-old man learned that suspects in the gang were getting information that appeared to come directly from police, and launched the investigation that led to Robinson. She was put on administrative leave last year and fired in March.