THE partner of convicted gangland murderer Brian Rattigan is at the centre of a major criminal investigation after the names and addresses of the jury who deliberated at his trial were found in her apartment.

Twenty-six-year-old Natasha McEnroe, from Drimnagh in Dublin, was released from garda custody late on Friday night. She had spent two days being questioned about why highly confidential personal details of the jury, who convicted her boyfriend of murder, were found in the apartment.

Her apartment in Adamstown, west Dublin, was raided by detectives last Wednesday night and the jury list, along with other confidential garda files, was discovered.

Garda commissioner Fachtna Murphy has ordered a massive investigation to find out how the list of names was made public.

Under legislation, only the defence lawyers, prosecution and the Courts Service are allowed to have possession of jury lists in order to ensure that personal details that might put jurors in danger are not leaked.

It is likely that gardaí will now offer security advice to the men and women who deliberated in the trial of Rattigan last November and December for the murder of Declan Gavin.

A previous jury who deliberated on the case could not agree on a verdict and was discharged. The murder trial was blighted by the intimidation of witnesses and gardaí and two officers were openly threatened with murder in court.

Brian Rattigan (26) was found guilty of the 2001 murder of Gavin, who was stabbed to death outside a fast-food outlet in Crumlin. It was the first murder in the so-called Crumlin/Drimnagh feud, which has claimed the lives of 16 people so far.

Fine Gael's Charlie Flanagan has described the finding of the jury list as "a very sinister development".

"It underlines reports that there have been attempts at jury intimidation. Juror intimidation is a very serious issue and it is obvious that organised criminals in Dublin and elsewhere will go to any length to subvert the criminal justice system.

"How somebody could obtain such sensitive information as to the home addresses and perhaps even contact numbers of jurors is of very serious concern. Steps should be taken by the authorities to protect jurors above all, and this certainly justifies to some extent the use of [the] non-jury special criminal court in gangland cases."

It is understood that Natasha McEnroe had no explanation as to how the confidential documents came into her apartment and she was released without charge.

She has been involved in a relationship with Rattigan for over a decade and the couple have one child together. He is serving a life sentence in prison.

She was arrested following the murder of Declan Gavin and told gardaí that the dead man "was a bleedin' rat" and whoever murdered him "should have got a motorbike and done it right. I hated him."

This is the first known case where the names and addresses of jurors in such a high-profile trial have been discovered in such circumstances and the development is of huge concern to gardaí.

During the trial of Rattigan last year, attempts were made to intimidate witnesses and gardaí involved in the case and Judge Barry White commented on this when the verdict was handed down.

Judge White jailed one Rattigan associate for contempt of court after he turned up in court each day and stared at jurors and potential witnesses in a blatant attempt at intimidation.

The judge is known to be angry about the intimidation. During a contempt of court hearing taken by Brian Rattigan against three newspapers last week, Judge White said that any offence committed by the papers "pales in comparison" to the "witness intimidation" during the Declan Gavin trial. He said he took a "very strong view" of the intimidation.

There have been widespread fears in political circles that there is the potential for jury intimidation in gangland trials. Justice minister Dermot Ahern introduced legislation last summer to allow gangland trials to take place before non-jury courts to prevent possible intimidation.