Ernie Waterworth, of the firm McCartan Turkington Breen, said six of these retired officers had sought legal advice with him.
Four of them are former Special Branch members and two of them detectives, he said.
He understands the documents contain the names and ranks of officers, but not addresses.
Whilst he knows of eight named officers in the documents, he added that “there’s maybe more”.
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Previously, the Police Federation had only said that it believed that multiple officers’ details had been stolen; it had not been clear how many or which branch of the force they worked in.
Mr Waterworth said all the officers he knows of in the documents are now retired.
There is a concern “their safety has been compromised” by the theft, he said, adding that they are “assessing their situation at the minute, because some of them may feel that they have to relocate”.
Mr Waterworth said he has sought clarification from the office of the ombudsman about the full extent of information which may have been taken, what kind of security classification it fell under, and what the police have done to try and recover all copies of the information.
The PSNI were asked if there are any updates in the investigation, but failed to respond by time of writing.
Alan McQuillan, a veteran RUC man who rose to the rank of second-in-command of the PSNI, said that while all officers face some degree of theft, ex-members of Special Branch would be seen as a “prestige target” by dissident republicans.
Meanwhile, Dr William Matchett, himself a former Special Branch member, said: “It is widely known that retired officers lost confidence in the Police Ombudsman’s Office long ago.
“They see it as arbitrary and unaccountable. Without question, more complaints will follow.”
The current scandal comes on the heels of other controversies.
These include the fact that last June the ombudsman had sparked the ire of many unionists when he issued a report concluding state collusion “is a significant feature of the Loughinisland murders” (carried out in 1994 by the UVF).
His finding of collusion was made as he simultaneously concluded that there was “no evidence the security forces were aware the UVF were planning to mount an attack in Loughinisland”.
Last August, a gun and ammunition were reportedly found in a filing cabinet at the ombudsman’s office. It is thought the gun had been been seized several years earlier during an investigation.
In response to the idea Dr Maguire should step down – raised by ex-MLAs Nelson McCausland and Ross Hussey – the ombudsman’s office said: “Both the PSNI and the Information Commissioner’s Office are carrying out independent investigations linked to the theft from this office.
“It is only when those processes have taken their course that we will know the facts of the matter and will be able to take an informed view. “