The case centred around payments to show favour for the tendering and continuation of CCTV contracts in Northern Ireland.
The joint investigation by the Serious Fraud Office and the Ministry of Defence Police, into bribery allegations began back in 2002.
The defendants in the case were:
James Daniel McGeown, owner of VIS Security Solutions Ltd, which obtained contracts worth a total of £16.2 million whilst he was paying bribes.
William Ronald Marks, the Deputy Senior Commercial Officer for the Ministry of Defence in Northern Ireland
John Symington, Senior Quantity Surveyor for the MOD and
Carol Kealey, the sister of William Ronald Marks.
McGeown pleaded guilty to 16 counts of corruption involving payments to MOD employees and paying bribes to Marks of £66,500 and Symington of £18,000.
Marks pleaded guilty to 11 counts of corruption and Symington to four counts.
A preliminary date for sentencing of the three offenders has been set for Friday 9th March 2012 at Belfast Crown Court.
The fourth defendant, Carol Kealey, admitted an offence of obstructing a police officer in the execution of his duty whilst investigating the financial affairs of Marks.
She was given a conditional discharge.
Commenting on the result SFO Director Richard Alderman said: “This has been a complex investigation involving a huge amount of evidence. I welcome the verdict which sends a clear message to people who divert public money to their own ends that they must face the consequences.”
The investigation was started by the Ministry of Defence Police in 2002 and due to its size and complexity, it referred the case to the SFO which took it on in September 2004.
Confiscation proceedings are fixed to take place at Belfast Crown Court on Wednesday 9th May 2012.