The senior Garda arrested over his alleged dealings with the media when members of the force took two Roma children from their families has been released from custody.
A Garda spokesman said the officer had been released without charge and a file is being prepared for the Director of Public Prosecutions.
The former Ombudsman for Children Emily Logan in a report published last July concluded information about one of two children taken from their homes in October 2013 in Westmeath and Dublin had "on the balance of probability" been disclosed by a member of the Garda to the journalist who wrote the initial reports on the first child being taken.
It went on to say that all parties involved in the case “regarded this development as deeply troubling and highly regrettable”.
The information reported did not lead to the children being taken. Instead, it confirmed the Garda had taken them, with the event becoming a major embarrassment to the force.
While she did not recommend a criminal investigation, Garda Commissioner Noirin O’Sullivan was quick to establish an inquiry.
That inquiry identified a senior officer based in Garda Headquarters, Phoenix Park, Dublin, as a suspect and it is he who was arrested at 7.30am on Thursday. He went to a Garda station in Dublin by arrangement.
The two Roma children were taken from their families by the Garda in October 2013 and briefly held in the care of the HSE before being returned when DNA evidence established the familial link.