The family of a woman murdered and secretly buried by the IRA over 40 years ago are to sue the police and the British Ministry of Defence.
Relatives of Jean McConville claim there was a negligent failure to hold a "prompt and efficient" investigation into her abduction.
Confirmation of the civil action came on the tenth anniversary of her remains finally being discovered at a Co Louth beach.
The mother-of-ten, one of the Disappeared, was taken from her west Belfast home in December 1972 on suspicion of being a British informant.
It is believed that she was tortured before being shot and buried.
Legal proceedings have been initiated against both the Chief Constable of the PSNI and the MoD over events surrounding her abduction, death and subsequent inquiries.
Solicitor Ciaran Mulholland said he has been instructed by members of the McConville family to pursue a claim over the "horrific events".
He claimed Mrs McConville was found by a British army patrol in the early hours of 1 December 1972 "roaming the streets in a state" after first being interrogated by the IRA.
She was taken to an RUC station at Queen Street in the city, but seized again later that day, according to Mr Mulholland.
He alleged that police were told of her abduction within hours, but refused to assist.
Further failures to act occurred over the next two months, it was claimed.
"The family still do not know the circumstances of this horrendous event: why was their mother taken? Why would the RUC not intervene or investigate the matter?" Mr Mulholland said.
"The McConville family firmly believe that the RUC and subsequently the PSNI have utterly failed to assist the family's quest for the truth."
"The family now feel that given the lengthy passage of time and the obstruction they continue to meet seeking the truth into the disappearance and murder of their mother that they have no alternative other than to hold the police and Ministry of Defence to account.
"Our clients' feel that legal action is now essential in their journey for truth, and accordingly representations have been sent to both the Chief Constable and the Ministry of Defence."