A cleaner found the body in a men's toilet at the stadium, according to multiple reports. The cleaner opened the door and saw a lifeless man lying on the floor. Police and paramedics were called immediately but could not help; the man had been dead for several hours.
Investigators believe the man was not a victim of homicide, with Bild reporting that he may have suffered a heart attack or stroke. The man had attended an event at the stadium on Wednesday evening, and his body may have lain in the toilet for several hours or even overnight. It is not known how no one noticed he stayed behind after the event or why he did not leave the stadium.
Schalke plays in the 2. Bundesliga, Germany's second-highest division. The club leads the league and is strongly positioned for direct promotion with four games remaining.
Schalke's last home match was on Sunday, April 19.