Loughgall families meet NIO to demand documents
Families representing eight IRA men and a civilian who were killed by undercover soldiers in 1987 are to meet government officials in Belfast later.
The families want new inquests and access to withheld government material.
The IRA men were shot dead by the SAS as they tried to bomb Loughgall police station in County Armagh. The civilian was caught in the gunfire.
'National security sensitive'
In July, Ms Villiers was criticised by nationalist politicians and campaign groups for what they viewed as her intervention in the case.
The families of the nine men have accused her of removing the decision on whether to open new inquests from Northern Ireland's attorney general, John Larkin QC, and passing it to Advocate General for Northern Ireland Jeremy Wright QC, who is also Attorney General for England and Wales.
On 5 September, Ms Villliers said the government had material, some of which was "national security sensitive" that would be relevant to any decision on whether to open fresh inquests into the cases.
She said she had written to Mr Larkin to inform him that she had issued a certificate, the legal effect of which was that Mr Wright would now take the decision on whether to grant new inquests.
'Right to truth'
However, the families of the nine men said they want all documentation related to the case "to be produced, reviewed and examined in an independent court of law".
"It is our right to know the truth about what happened to our loved ones and for all documents connected to the incident to be made available for review," they said in a statement.
They had asked for a meeting with Ms Villiers, but are due to meet officials from the Northern Ireland Office (NIO) at Stormont House on Thursday afternoon.
"We want the NIO officials to explain what this material is, where it is held and why it is deemed 'relevant and national security sensitive'," the families' statement said.
"We want to know if this material has been withheld from the original inquest, from the Historical Enquiries Team and from the director of Public Prosecutions."
On 5 September, the NIO issued as statement saying Ms Villiers' role as secretary of state was "simply to make sure that the appropriate law officer is able to take the decision, with all of the information available, independent of government".
The statement added that Ms Villiers "having fulfilled the requirements placed on her by the legislation, has no further role to play in relation to the decision whether to direct these inquests".
The IRA men were shot as they approached Loughgall police station with a 200lb bomb in the bucket of a hijacked digger in May 1987.
A civilian, Anthony Hughes, was killed and his brother badly wounded when they were caught up in the gunfire.
His family received a full government apology earlier this year.