The DUP is to press the attorney general for a parliamentary statement on the decision to drop charges linked to an alleged IRA spy ring at Stormont.
DUP MEP Jim Allister wants to meet the attorney general
Three men were acquitted on Thursday when the prosecution offered no evidence "in the public interest".
The men, whose arrests led to the collapse of the power-sharing executive in 2002, claimed the case against them had been politically motivated.
The DUP also wants to meet the Director of Public Prosecutions over the matter.
Speaking on BBC Radio Ulster's Inside Politics, the party's MEP, Jim Allister, said the DUP had asked for a meeting with DPP Sir Alasdair Fraser.
"We will pursue, through parliament, questions to the attorney general (Lord Goldsmith), because one would believe that he would have been involved in the decision.
"Of course, there is that grey area as far as the attorney general's role is concerned, when at one time he is a law officer and at another he is a politician."
Sinn Fein's Denis Donaldson, son-in-law Ciaran Kearney along with William Mackessy had a total of seven charges against them dropped on Thursday.
Police raided Sinn Fein offices at Stormont in October 2002
Mr Donaldson said his charges were dropped due to the prosecution's "self interest". He may now sue the police.
"It was part of a Save Dave (Trimble) campaign initially and it was also designed to bring down the (power-sharing) institutions, which it did," he said.
Irish PM Bertie Ahern said on Friday that the affair had caused him and Tony Blair "huge grief".
"It was a lot of grief for no prosecutions," he told reporters after meeting Mr Blair at Downing Street.
The three were arrested following a police raid on Sinn Fein's offices at Parliament Buildings on 4 October 2002, when documents and computer discs were seized.
The arrests led to the power-sharing executive at Stormont being suspended, after the DUP and Ulster Unionists, led at that time by Mr Trimble, threatened to collapse the executive with resignations.
The SDLP's Alex Attwood said his party was also seeking a meeting with Attorney General Lord Goldsmith.
"What were the factors that gave rise to the decision? Was there an effort being made to protect individuals either in the British government or acting on behalf of the British state in order for these charges to go away?" he said.
The Public Prosecution Service said it would be making no further statement in relation to the decision to drop the charges.
A spokesman would not respond to allegations that the service had bowed to political pressure.
He would not clarify what it regarded as the nature of the public interest which led to the charges being dropped.