A judge dismissed charges against former Chattanooga detective Karl Fields on Friday afternoon.
Criminal Court Judge Barry Steelman said the state had not proven its case.
Fields, who was earlier dismissed from the Chattanooga Police Department, had been charged with tampering with evidence and official misconduct.
The jury in the case never got to deliberate after attorney Jerry Tidwell asked the judge for a dismissal of both charges.
The case was tried by a prosecutor from Roane County.
It was claimed that Fields hid evidence that was favorable to a man charged with rape so that he could continue a romantic relationship with the alleged rape victim.