The man named in court as an MI5 agent is thought to have been working undercover in Northern Ireland for almost ten years.
The Irish News also understands that Dennis McFadden had involvement in a bar on the outskirts of Belfast and part-owned a second bar on the Spanish island of Gran Canaria.
Originally from Glasgow, he had been living in Glengormley, Co Antrim, until he disappeared a few weeks ago ahead of a major operation against the New IRA.
Eight men and two women are charged in connection with the MI5 led operation, linked to two meetings in Co Tyrone in February and July.
Mr McFadden is said to have organised the meetings and transported people to the venues which were bugged by MI5.
The Scottish agent has been active in republican circles since the early 2000s.
He was a close friend of veteran IRA man Tony TC Catney and stayed with him in his west Belfast home before he died in 2014.
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Catney was believed to be a senior member of the New IRA.
It was this high level endorsement which allowed McFadden to infiltrate the Real IRA which later merged to become the New IRA.
McFadden claimed he worked as a hotel safety inspector, and used this as a cover for his frequent travel.
He had served as a special constable in Scotland in his early 20s and although some republicans raised suspicions, he was appointed a 'resource officer'.
Providing so called 'safe houses' and transport for meetings, he was also often seen in a yellow vest providing stewarding at republican marches.
It is believed that rather than having been 'turned' by the security services, he may have been an agent from the outset and infiltrated the New IRA as far back as its formation in 2012.
During recordings used in the arrests of nine people alleged to be members of the New IRA along with a Palestinian doctor, McFadden is said to be "cool as a cucumber" throughout.
McFadden's Glengormley homes now lies empty, neighbours reporting that a removal van arrived last Wednesday, the day after nine people were arrested, and took all his belongings.
