German police have launched an investigation for attempted manslaughter after Galatasaray fans threw firecrackers and smoke bombs onto the pitch and into the Borussia Dortmund spectators during the Turks' 4-1 loss on Tuesday.
Edzard Freyhoff, Dortmund police chief, said trouble started in the city centre before the Champions League game when a group of about 800 Galatasaray fans lit bangers and smoke bombs before marching towards the stadium.
The Group D game was interrupted twice for a few minutes while the Turkish team's players went to the supporters in an effort to make them stop.
"Among other investigations were (those) launched into attempted manslaughter, disturbing the peace, breaking laws regulating explosives and laws on assembly," Dortmund police had said earlier.
The Turkish club could face sanctions as well as a fine from UEFA.