Julian Nagelsmann has hit out at a 'mole' in the dressing room after Bayern Munich's tactical plans were published by German media.
While Bayern have famously used a 4-2-3-1 system for over a decade, the 35-year-old revamped their style earlier this year once it became less effective.
Some documents showing how the Bundesliga club changed their working were leaked, and ended up on the German site Bild. They were issued to players to highlight their tactical demands, and a specific route of play.
The publication of Bayern's strategy has greatly annoyed Nagelsmann, with the issue blamed on a mole within the German club's camp.
As Bild reported, the 35-year-old manager told reporters: 'It bothers me a lot. The person who transmits this harms each of the players, he is not the objective.
'What is the person who transmits this looking for? What are you waiting for? I don't see what his motivation could be, beyond facilitating the task for the adversary.'
Nagelsmann also spoke about the problems that Bayern would have finding the sneak. He said: 'Moles are protected species. Every time you drive through the countryside, you see 80,000 moles and you can't get rid of them. Their search is very, very difficult.'
Nagelsmann said it was his endeavour to find out the reason behind the leak, calling the incident 'a betrayal of football codes'.
Then he added: 'I hope that this person can't look in the mirror because it's not fair.'
Nagelsmann took over the helm at Bayern Munich in 2021, overseeing last year's trophy lift of the German top flight.
His side sit top of the Bundesliga this term, ahead of Sunday's trip to mid-table side Bayer Leverkusen.
Following Friday's Champions League draw, Bayern know that they face Premier League opposition in the quarter-finals against Manchester City.
German legend Lothar Matthaus said the Bavarian side 'do not need to be afraid' of Erling Haaland despite the Norwegian's high-scoring prowess in the English top-flight.
After their last-16 victory over PSG, Nagelsmann said his tactics were crucial in freezing out Lionel Messi and Kylian Mbappe.
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