Chelsea are angry over claims from Germany about the negotiating tactics of managing director Marina Granovskaia.
Reports in Germany claimed the Blues director is searching for weaknesses inside the Bayer boardroom to help in the deal for Kai Havertz.
Chelsea categorically denied Ms Granovskaia is compiling any document on any individual.
A Chelsea source later told The Sun “that is absolutely not the way she does business.”
Bild had earlier claimed Ms Granovskaia has compiled a dossier on Leverkusen’s flaws to help push the deal through.
Roman Abramovich’s most trusted advisor at the club, the Russian-Canadian has already overseen deals for Timo Werner and Hakim Ziyech this summer.