A 34-year-old teacher with whom Buckle had an affair for some time had accused him of raping her and threatening to kill her with his licensed firearm.
The woman said Buckle took her to a house in Belvedere, St Andrew, on August 5, last year and raped her.
Under cross-examination by defence lawyers Tom Tavares Finson and Peter Champagnie, the woman admitted she was involved in an intimate relationship with Buckle.
After the Crown closed its case yesterday, the defence lawyers referred to several discrepancies and inconsistencies in the complainant's evidence.
The defence lawyers argued that no tribunal properly directed could convict Buckle based on the evidence given.
Justice Ingrid Mangatal upheld the no-case submission and freed Buckle.
Buckle was accused of committing the offence about a year after he resigned from the police force.