But the judge who heard the case is not convinced she is innocent.
Last month, Karis Rewa Charnley, 40, appeared in the North Shore District Court in a hearing before Judge Brian Callaghan to defend the charge against her.
It was alleged that in February, she gave Cameron Ross, a violent criminal on bail, her police uniform and an impound notice pad, which he used to steal an $11,000 car belonging to her son's friend, Jerome Kino.
Police said she then tried to get her son to burn the items in a bid to destroy evidence.
But Ms Charnley, who was suspended from duty after police bosses found out about an "inappropriate relationship" she was having with a criminal, denied any involvement in the crime.
She claimed Ross, her then-boyfriend, stole the items without her knowing. When she found out, she tried to get rid of them so she would not be connected to a crime she had not committed.
She said Ross was violent towards her and she was too scared to report him. As well, she did not think the police would believe her as she was suspended from duty and facing disciplinary action at the time.
In June, Ross pleaded guilty to stealing the car and to impersonating a police officer, and was jailed for 12 months.
At the end of Ms Charnley's hearing, Judge Callaghan said the case was complex and he wanted to go over the evidence again, so he reserved his decision.
The Herald has obtained a copy of that decision, in which the judge said there were two possibilities - that Ms Charnley was "in cohorts" [sic] with Ross and got cold feet when she found out the stolen car belonged to her son's friend, or that Ross stole her property without her knowing.
Both versions of events were viable, but "the defendant's demeanour in the witness stand was not convincing".
"I cannot say that I am convinced about the defendant's explanation. I remain suspicious ... but I am unable to be sure that she took part in the pre-planning of the offending generally and that she knew that Mr Ross [was] going to offend by lending [him] her police uniform," Judge Callaghan said.
"So therefore I have reasonable doubt about this. The prosecution has failed to prove these charges beyond reasonable doubt, and they are dismissed."
He said that as Ms Charnley was charged as a party to the theft, police had to prove that she actively assisted or encouraged Ross to commit the offences.
"It was suggested to her that she helped Mr Ross because of her close attachment to him and her disillusionment with the police over her suspension. She did not accept these matters.
"There is no evidence suggesting she was an active participant in the offending, [that] she was there when the car was taken ...
"There is no direct evidence linking her to the theft itself, including the impersonation by Mr Ross."
Ms Charnley did not respond to messages yesterday and her lawyer, John Moroney, refused to comment.
Her former police boss, North Shore area commander Inspector Les Paterson, stood by the police handling of the case. "Laying the charges was the correct thing to do in both law and policy," he said. "The judge was faced with a difficult job and we are grateful that he took the time to very carefully consider the matter."
Ms Charnley met Ross when she was working at court and he was waiting for a bail hearing, and they started a sexual relationship.
She resigned from the police in May.