A DOCUMENT purporting to be from a major police data breach in Northern Ireland was posted overnight on a wall facing a Sinn Fein office in Belfast, in what the party described as a “sinister” attempt to intimidate.

Gerry Kelly, who is the party’s policing spokesperson, said the redacted document had been put up outside his North Belfast office and included a photograph of him alongside a threatening message.

Last week, the Police Service of Northern Ireland (PSNI) revealed that a document had been mistakenly shared online, revealing the names and professional details, including locations and duties of every single police officer and civilian staff at the force.

Some 10,000 people had their details revealed by the inadvertent disclosure – including police supporting MI5 and undercover officers.

Kelly said: “This is a very obvious attempt by dissident republicans to intimidate me.

“Even more sinister, this is a very public indication that the dissidents do have access to the sensitive information in the data leak document. It therefore represents a very real threat to the officers and the civilian staff involved.

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“I have of course reported this incident to the PSNI and I would appeal to anyone with information to bring that information forward.

“Sinn Fen represents the vast majority of people in the nationalist community and we will certainly not be intimidated by dissident groups who have virtually no support and who offer nothing but disruption and threats in an attempt to make themselves relevant.

“They should disband and end their anti-community activities.”

Later on Monday afternoon, PSNI Chief Constable Simon Byrne said he was confident that the information was now in the hands of dissident republicans.

Byrne said: “We are obviously investigating where we think this leak went but we’ve said from last week there was an assumption that this would get into the wrong hands, and we’re now just confirming that.”

Scores of officers have expressed concern for their safety in Northern Ireland, where police are under threat from terrorists – with the current level of threat assessed as severe, meaning an attack is highly likely.

Assistant Chief Constable Chris Todd said: “We are aware that some redacted information from the Tuesday August 8 data breach has allegedly been posted on a wall in west Belfast today, Monday, August 14.

“We have commenced an investigation into this matter.

“From the outset we have been planning for this potential development and that plan is now being put into place.

“We recognise the impact this may have on our officers, staff and their families and additional security and reassurance patrols have already been implemented across Northern Ireland as part of our organisational response.

“The safety and welfare of our officers and staff remains our priority and we have reminded them of their personal safety and security both on and off duty.”