A body has been recovered from a car in the Newry Canal by police investigating the disappearance of Gareth O'Connor.
The father of two disappeared after leaving his home in Armagh City in May 2003.
He was reported missing after he failed to report to Dundalk police station in the Irish Republic as part of his bail conditions.
Mr O'Connor had been charged with membership of the IRA.
Police confirmed the car was similar to the one the missing man was last seen in.
A police spokeswoman said search teams had recovered the Volkswagen Golf and a body from the canal off the Omeath Road.
A post mortem is due to be carried out to determine the cause of death. No formal identification has been made, the police spokeswoman said.
But she added the O'Connor family were being kept up-to-date with developments.
It is understood the search operation was sparked following intelligence received by detectives probing the Armagh man's disappearance.
Police believe the 24-year-old was abducted and murdered after being kidnapped by the IRA.
Searches on both sides of the border failed to reveal the whereabouts of Mr O'Connor.
In September 2003, the IRA issued a statement denying they killed the Armagh man.
Police search teams, including an underwater unit, spent several hours searching the canal outside Newry before recovering the car.
A spokeswoman for the PSNI confirmed the car was a blue Volkswagen Golf. But she said detectives were unable to say if it belonged to Mr O'Connor.
The vehicle was removed for forensic examination.