The ghost players of Apollon Limassol have added a new twist to football's complex transfer lore and attracted the scrutiny of the sport's world governing body.

Under deals first disclosed by investigative reporters last year, players under contract with the Cypriot former champions have never played or trained with the club and some have never even set foot in the country.

Who knew that Luka Jovic, the so-called 'Serbian Falcao' who made his debut for Red Star Belgrade as a brilliant 16-year-old, was actually under contract with Limassol when he transferred to Portuguese giants Benfica last year?

The Black Sea, an online site linked to the investigative consortium Football Leaks, recorded seven similar 'virtual' transfer deals involving Limassol and players from Serbia and Romania.

Under the Jovic deal, struggling Red Star were in desperate need of cash, according to Le Soir newspaper in Belgium.

Up stepped Apollon and agreed to front up two million euros for Jovic, acting as a third party to ease Red Star's immediate cash crunch. Jovic never set foot in Cyprus and when the transfer to Benfica went through the following year, Limassol pocketed a handsome 4.65 million euros, Le Soir reported.

The deal appears to be a variant of Third Party Ownership (TPO), a practice outlawed by FIFA in 2015 whereby outside investors buy into players' contracts in the hope of future profits.

Limassol, linked to super agent Pini Zahavi who was involved in the world record transfer of Neymar to Paris Saint-Germain over the sumer, have been hyperactive in the transfer market.

But the figures show a clear pattern -- in September alone, 29 players joined the club while 28 left, according to specialist site Transfermarkt.

- Cypriot ghosts not alone -

FIFA said an investigation into the transfer activities of the Cypriot club was underway, with a spokesman adding that "the matter has been referred to the disciplinary commission."

Third Party Ownership emerged in football when bank financing dried up following the 2008 financial crisis, according to football finance expert Shervine Nafissi.

Investors operating often from tax havens stepped in to replace the banks in the hopes of making a profit down the road.

"It really took off in 2008 when the crisis came and banks become more and more reticent about lending to clubs," he said.

Banned in 2015, the practice appears to be making a comeback under a new guise, with clubs taking over from investors as the third party.

Limassol declined to speak to AFP about the transfer activities.

However, the Black Sea publication said: "Cypriot club Apollon spears to be transferring players for non-sporting reasons."

The Cyprus ghosts are not alone. Obscure contract arrangements are also haunting the transfer dealings of other clubs.

In Latin America a non-sporting transfer can result in a hefty tax gain. An Argentinian club would think twice these days about selling a player directly to Europe.

It would cut tax payments from seven percent to two percent if he were first sold to a Uruguay club, according to a French website Lucarne Opposee which specialises in South America football.