NEWCASTLE Jets owner Con Constantine has admitted that he swore at a group of Jets fans and threatened to throw one of them off the balcony of his private box during Sunday's match at EnergyAustralia Stadium.Football Federation Australia (FFA) has confirmed it is investigating the incident involving Mr Constantine and five leading members of the Squadron supporters group.One of those present, Nigel Bosworth, described the tirade as disgusting, abusive and arrogant."No one should ever have to put up with that sort of abuse, let alone the most loyal supporters of the club," Mr Bosworth said.Mr Constantine confirmed the details of the incident yesterday.He said he had called Squadron president Tim Versheleden to his box during the first half to discuss fan protests taking place around the stadium.He admitted to abusing Mr Versheleden and the four other fans, but told The Herald yesterday he remained firm in a threat to ban any disloyal troublemakers for life.When asked if he had threatened to throw Mr Versheleden from the box, Mr Constantine replied: "Yeah, when you're upset with someone you say a lot of things."I swore at them because I knew they were wrong," he said."At the end of the night Timmy and his family came back to the club, so he obviously didn't take it too badly."Mr Constantine said there was no room for troublemakers at the club, and that a number of fans were on a last warning.The protests that angered Mr Constantine, described as "ironic" and "tongue-in-cheek" by Squadron members yesterday, included placing three banners upside down on the eastern grandstand, and fans waving white handkerchiefs.Security guards removed the banners during the first half.Also taken down was a non-Squadron banner on the western grandstand that read "Newcastle Jets: We've Been Conned", indicating frustration with the team's performance.Another fan brought a two-metre high wooden spoon to the match.Mr Constantine said such protests "killed the credibility" of the club."If they think for one minute that I'm happy that I got the wooden spoon, they should know I'm a bad loser," Mr Constantine said."If they have an issue with the club they could have come and addressed it with me."Mr Bosworth responded to claims of disloyalty by saying the supporters were loyal to Newcastle and the team, not Mr Constantine."It disgusts me to see a club that I support, and that represents the town I grew up in, be so low to people over an issue as trivial as a few banners turned upside down," Mr Bosworth said."Many of us have had a go at the club over their problems in the past few weeks, but up until the events on Sunday, we've held out hope that this was . . . just a bad year in the rollercoaster-ride history of football in Newcastle."Squadron member Gavin Austin said many of Mr Constantine's comments were made in the heat of the moment, but described the way he treated the fans as "unbelievable"."I think the thing that upset us the most was the way we chose to demonstrate [our unhappiness] was in a pleasant way," Mr Austin said."If we instigated it then his reaction was a lot worse."An FFA spokeswoman confirmed an investigation was under way."We have been advised of an alleged incident involving Mr Constantine and we've asked the club for further information," she said.The spokeswoman confirmed the FFA would also speak to the fans involved.Of greater concern to the club's management may be that the incident appears to have exposed a rift between management and fans who have been frustrated by several high-profile departures and forced to watch their side fall from champions to wooden spooners within a season.After the incident, the Squadron vacated their usual bay and members chanted for the removal of Mr Constantine and coach Gary van Egmond.Jets supporters also flooded a popular internet forum yesterday, and many joined in calls for Mr Constantine to sell the club.Mr Constantine said fans would be impressed by the amount of work going into the club's upcoming Asian Champions League campaign."We're doing a lot of things behind the scenes for the Asian [Champions League]."