PSNI Chief Constable Simon Byrne has said he is confident that information on police officers and staff mistakenly released in a major data breach is in the hands of dissident republicans.
At a press conference in Belfast Mr Byrne said he believed dissidents would use the information to intimidate and target police.
Last week the Police Service of Northern Ireland (PSNI) revealed a document had mistakenly been shared online which included the names of about 10,000 officers and staff.
Details released included the surname and first initial of every employee, their rank or grade, where they are based and the unit they work in.
It is, therefore, a planning assumption that they will use this list to generate fear and uncertainty as well as intimidating or targeting officers and staff— PSNI Chief Constable Simon Byrne
Mr Byrne said: “I would like to confirm the picture in relation to last week’s breach continues to evolve at pace.
“We are now confident that the workforce dataset is in the hands of dissident republicans.
“It is, therefore, a planning assumption that they will use this list to generate fear and uncertainty as well as intimidating or targeting officers and staff.”
The Secretary of State for Northern Ireland, Chris Heaton-Harris, has said he is in close contact with Mr Byrne and his senior team over the matter.
In a statement on Monday, Mr Heaton-Harris said: “The UK Government remains committed to providing specialist support and expertise, and I know that PSNI and security partners will continue to take proportionate action to protect officers and staff and their families.”
Mr Byrne said the PSNI “will continue to adapt our posture and our tactics as the information changes”.
Mr Byrne said the PSNI is “working around the clock” to assess the risk to staff.
“We have measures in place to reassure and advise our workforce of what this risk means for them. We will continue to liaise with the policing board and the UK Government as well as other partners as we develop our response to this matter.”
He said the PSNI had been given a “green light” by the UK government to take new measures to protect staff, and that he was confident it would be “standing by” if that included additional finances.
Mr Byrne said measures had been put in place to advise all members of the workforce, but the PSNI had not “caught up” with 45 members at the start of Monday.
He said the data did not contain information on retired colleagues.
The update follows the posting of redacted information, purportedly from the breach, on the wall of a library in Belfast.
Mr Byrne said: “Clearly, that was the first indication that started to vindicate our planning assumption that this list had falling into the wrong hands.”
Sinn Fein MLA Gerry Kelly said the document, which was posted overnight close to the Sinn Fein office in the Falls Road, included information about a “substantial number” of police officers and staff, although their names had been removed.
The latest revelation in the controversy which has rocked the PSNI comes as it has emerged that almost 3,000 police officers have inquired about potential damages following the massive data leak.
Policing Board member Mr Kelly, who described the posting of the information as “sinister”, said he saw the posting of the information as a “threat by dissidents”.
I look upon this as a threat by dissidents to me and I will not be intimidated— Sinn Fein MLA Gerry Kelly
“There was a photograph of myself and then there was a statement saying in large writing: ‘Gerry, we know who your mates are’.
“Under that there was what appeared to be, and what turned out to be, a section of the leaked documents that were put out.”
Mr Kelly added: “I look upon this as a threat by dissidents to me and I will not be intimidated.
“More serious is that this is the dissidents, or whoever is involved, putting out that their claim that they have access to the leaked documents, they are putting out a verification on that.
“I think that is their main intention.”
Assistant Chief Constable Chris Todd confirmed that an investigation has begun into the posting of the redacted information in Belfast.
Hundreds 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.
The Police Federation of Northern Ireland, which represents rank and file PSNI officers, that by Monday afternoon 2,905 officers had expressed an interest in the event of legal action following the major data breach.
PFNI chairman Liam Kelly said the confirmation the data was in the hands of dissident republicans was a “deeply worrying development”.
He said: “We have to be strong and determined to do everything we can to minimise risk and that means varying the routes we take to and from work, changing routines and re-assessing our personal security both on and off duty.”
While no legal action has yet commenced, it is thought officers and staff whose names and places of work were revealed could be in line for compensation.
The PSNI is already facing significant budget pressures and any settlements would be expected to run into tens of millions of pounds.
Shadow Northern Ireland secretary Peter Kyle said support for PSNI staff “must be the priority in this extremely challenging moment”.
He added: “There are many questions that need to be answered about how this terrible situation has come about, but the first and most important response that is required is to ensure the safety and security of PSNI officers and staff who are affected.”
