DFB investigates Roger Schmidt over referee row

Leverkusen's clash with Borussia Dortmund on Sunday was halted for nearly 10 minutes in the second half after official Felix Zwayer took the players off the pitch following Schmidt's refusal to leave the technical area.

The 48-year-old apologised after the match but explained that he was frustrated to have been sent to the stands without being given an explanation in person by the referee.

"The monitoring committee of the DFB has begun an investigation into Roger Schmidt, the coach of Bayer Leverkusen," a DFB statement on Monday confirmed.

"The committee has written to Schmidt to ask for a timely explanation. After the presentation and review of the explanation, the panel will decide on a further course of proceedings."

Zwayer claimed he had asked Schmidt to leave the dugout "several times" before he was forced to bring a halt to the match.

The former Red Bull Salzburg coach had been incensed over the awarding of a free-kick in the build-up to Pierre-Emerick Aubameyang's winner for Dortmund, prompting the referee to take action.

The DFB later confirmed that they are also investigating sporting director Rudi Voller over comments he made about Zwayer after the match.

Voller had been left incensed after Leverkusen penalty appeals were waved away following the restart, and suggested to Sky Sport that Zwayer "wanted to get revenge" by refusing to award the decision.