Alexandria criminal court acquitted on Tuesday ex-national security officer Hossam El-Shennawy in a retrial on charges of torturing to death detainee Sayed Bilal.
El-Shennawy had received a 15-year sentence, which he appealed. He was granted a retrial in the case and has now been acquitted.
The sentence can still be appealed by the prosecution.
Another officer, Osama El-Kenisy, was previously acquitted on the same case after he appealed his 15-year sentence.
Sayed Bilal was arrested on 5 January 2011 and tortured to death while being interrogated by the now-dissolved State Security Investigations Services.
Bilal was being investigated for the bombing of the Two Saints Church in Alexandria on New Year's Eve that left more than 20 dead five days earlier.