Legal advice behind a decision not to take action against a Sinn Fein Policing Board member over a controversial tweet will not be disclosed.
Justice Minister Naomi Long was facing calls to publish the advice yesterday after confirming that Gerry Kelly would not face any further action over claims of "glorifying terrorism".
In September the North Belfast MLA tweeted about the anniversary of a mass breakout from the Maze prison.
Mr Kelly was one of 38 republican prisoners who escaped from the Maze in 1983. Prison officer James Ferris died of a heart attack after being stabbed while attempting to stop the breakout.
Mr Kelly described the prison break in his tweet as "one of Big Bob's best ops", referring to late senior republican Bobby Storey, adding: "I had the privilege of the front passenger seat."
The tweet had been subject to a probe by the Policing Board, but the matter was subsequently referred to the Department of Justice.
Yesterday Ms Long, who at the time stated that she found Mr Kelly's tweet "offensive", explained there are "insufficient grounds" for any action to be taken.
The development has been met with criticism from unionists, including UUP Policing Board member Mike Nesbitt and TUV leader Jim Allister, who have urged Ms Long to disclose the legal advice.
The Justice Minister explained: "It is important to note that the test to be applied for whether there has been a breach of the code is considerably different in law to the test to be applied by me for removal of a member of the board from office, the latter being significantly higher: any decision by me would also be subject to review by the courts."
She added: "Having considered that advice, it is clear that there are insufficient grounds even for holding an investigation into whether Mr Kelly should be removed from the Policing Board as the tweet, taken in the round with other statements of Mr Kelly, did not explicitly demonstrate a non-commitment to non-violence and exclusively peaceful and democratic means or otherwise suggest that there would be grounds to consider statutory removal."
Ms Long reiterated that she found the tweet "offensive", but she "must act in line with established legal standards".
"On that basis, I have accepted the legal advice provided and will not be taking further action," she added
DUP Policing Board member Mervyn Storey, who was one of the members to raise complaints, said that Ms Long needed to further explain the decision.
Meanwhile, Mr Nesbitt and Mr Allister both challenged Ms Long to publish the legal advice which led to her decision.
"Unless the Justice Minister is prepared to publish the legal advice she has received, she will be open to accusations of hiding behind it," said Mr Nesbitt.
Mr Allister said: "She should publish the advice. As the recipient, Naomi Long can wave privilege.
"Let the public see just why it is thought acceptable for a member of the Policing Board to joke about an event in which a prison officer was shot in the head and another died after suffering a heart attack during the breakout.
"This is yet another incident which will have many people asking fundamental questions about the nature of politics in Northern Ireland. Just why is it that Sinn Fein are untouchable?"
In response a DoJ spokesperson said: "Legal advice is privileged. The DoJ does not disclose any legal advice provided."
A spokesperson for the Policing Board confirmed that it had been notified by Ms Long of the decision.