Facebook did not view a post linking the management of Quinn Industrial Holdings and "the notorious Shankill Butchers" as violating their rules, it is understood.
QIH tried for years to have the 'Sean Quinn Community Page' removed but it was only taken down after the shocking kidnap and attack on chief operating officer Kevin Lunney from Fermanagh.
Gardai and the PSNI are now expected to request data from the social media giant in an effort to identify who moderated the page.
Although it sought to promote the return of Mr Quinn to his former business, he had no involvement in the Facebook page.
Material published on the page sought to vilify the current management team, including Mr Lunney. A message posted last September claimed five named executives had been the subject of a 'kangaroo court' which found against them.
It said: "In the early eighties we had the notorious Shankill Butchers, based in Belfast they were led by a man called Lenny Murphy. Now… based in Derrylin we have the Derrylin Butchers have (sic), and continue to stab Sean Quinn in the back."
The post claimed "this gang" was led by local men Kevin Lunney and Liam McCaffery, with the help of Tony Lunney, John McCartin and Dara O'Reilly.
"Rumour has it they have gone through a kangaroo court and have been found guilty. Their sentence will be based on how quickly they remove their knives from Sean Quinn's back, how quickly they plead guilty, and how quickly they vacate the business and land that they have stolen," the post said. It included images of the five businessmen.
Complaints were made to Facebook about the message but the company did not see fit to remove it because it did not amount to a direct threat.
It's understood Facebook did remove several other posts in recent years. However, the Shankill message was judged not to have crossed the required threshold to be taken down. The entire Facebook page was deleted on Monday for violating authenticity polices rather than any of its content.
A Facebook spokesperson said: "There is absolutely no place on Facebook for threatening behaviour. Over the past few years, following reports, we have investigated and removed a significant number of posts about senior executives of Quinn Industrial Holdings for violating our community standards.
"We have also provided relevant information to Quinn Industrial Holdings' legal team in accordance with court orders."
QIH welcomed the fact the removal of the page but a spokesman said Facebook has cause for "very significant reflection having failed to remove threatening material from its platform, including references to a 'kangaroo court passing sentence'".