The German Football Association (DFB) has opened investigations against Bayer Leverkusen coach Roger Schmidt and sporting director Rudi Voller following the controversy surrounding their side's 1-0 Bundesliga defeat against Borussia Dortmund.
The clash between the two teams on Sunday came to a halt when Leverkusen boss Schmidt refused to leave the field after being sent off by referee Felix Zwayer.
Schmidt had already been warned by Zwayer when he protested against Dortmund's 64th-minute goal. The goal was scored by Pierre-Emerick Aubameyang after BVB took a quick free kick in their own half 5.8 metres away from where Leverkusen forward Stefan Kiessling had fouled Sven Bender.
Despite being informed by Leverkusen captain Kiessling to leave the pitch twice, Schmidt refused and Zwayer, following the rulebook, opted to take the players off the pitch. After a nine-minute break, they returned to the field as Schmidt stayed behind in the dressing room.
In the remaining 25 minutes, Leverkusen were denied a penalty after Dortmund's Sokratis Papastathopoulos appeared to play the ball with his arm inside the box.
This led to furious protests from Voller, who seemed to suggest the decision was a consequence of Leverkusen's previous misbehaviour and argued that the referee was not neutral.
On Monday, German refereeing chief Herbert Fandel told the DFB website that he is still "lost for words" about what happened, while he bemoaned that match officials have been treated with dwindling respect this season.
"It's a downward spiral," he said.
The DFB announced on Monday that it has opened investigations against Schmidt and Voller, and said that sanctions for the Leverkusen coach could include a dugout ban or even a ban from working with his team.
Schmidt and Voller have been asked for a statement, and it is expected that the DFB will announce the punishments either on Tuesday or Wednesday.
The DFB has also opened an investigation against Hannover forward Hugo Almeida, who appeared to elbow an opponent in his side's 1-0 defeat to Augsburg on Sunday, with referee Daniel Siebert failing to spot the incident.