Warit "Todd" Uttapa had faced a misdemeanor charge of searching a criminal database without authorization.
Alameda County District Attorney Nancy O'Malley said in September that Uttapa would be among seven current or former police officers or sheriff's deputies who would be charged for alleged misconduct involving Jasmine Abuslin, the daughter of an Oakland police dispatcher.
But on Friday, a spokeswoman for the district attorney said: "Certain facts regarding the accessed information recently came to light, and have led us to the conclusion that we are not able to proceed with the filing of criminal charges."
Six others current or former officers have been charged by O'Malley.
Contra Costa County District Attorney Mark Peterson also declined to file charges against Uttapa or any current or former other law-enforcement officers with the exception of an 81-year-old retired Oakland police captain. That captain was charged with paying Abuslin for sex at a Richmond hotel.