The German Football Association is investigating England midfielder Jude Bellingham’s comments about referee Felix Zwayer after Borussia Dortmund’s 3-2 defeat by Bayern Munich.
Bellingham, 18, questioned Zwayer’s appointment, referring to his six-month ban for a match-fixing scandal in 2005.
Zwayer rejected Dortmund’s appeals for a penalty before giving their rivals a spot-kick for a Mats Hummels handball.
Robert Lewandowski scored the penalty to secure victory for Bayern.
Speaking to Viaplay, Bellingham said:
“You give a referee, that has match fixed before, the biggest game in Germany. What do you expect?”
Bayern’s win in Der Klassiker on Saturday saw them move four points clear of Dortmund at the top of the Bundesliga.
“For me, it wasn’t [a penalty]. He [Hummels] is not even looking at the ball and he’s fighting to get it and it hits him,” added Bellingham.
“You can look at a lot of the decisions in the game.”