The claims arrive after it emerged Keita has registered a company in the UK.
A company under the name 'NK8 LIMITED' has been registered on the Companies House website. Two people are listed as officers - Naby Deco Keita and Bjorn Alexander Bezemer.
And the website states Keita was appointed as a director on January 11.
Respected German football expert Raphael Honigstein wrote on Twitter: “interesting. it's legit."