Nuala O'Loan's office has been cleared of leaking confidential details concerning the investigation into RUC/loyalist collusion which she published in January.
Police began an investigation into the Ombudsman's Office handling of the report after the Retired Police Officers Association claimed details had been leaked to the press and the ombudsman was accused of being in breach of both the Official Secrets Act and the Police Act.
Her report was prompted by a complaint made by Raymond McCord snr that the murder of his son by loyalist paramilitaries had not been properly handled. Mrs O'Loan's report soon widened into an investigation concerning up to 16 murders by the UVF in north Belfast.
The police report concluded: "The PSNI has completed a thorough investigation and all parties involved have been informed of the outcome of that investigation.
"It would not be appropriate for a police organisation to comment further on the details or outcome." Mrs O'Loan said she remained confident that neither she nor her staff had acted outside the law.
"I had expected this outcome but nevertheless I am very pleased to have received the news that police have found no substance to the allegations," she told the BBC.
"The allegations made against me and my staff were very, very serious - I knew that the very small group of staff who had worked on the particular investigation had worked very hard and very closely, and I knew there was no substance to it."