Former Bayer Leverkusen coach Sascha Lewandowski has been found dead at his home in Bochum, Germany, aged 44.
Lewandowski left his role as Union Berlin coach in March, after six months in charge, on medical advice because of acute fatigue syndrome.
Club president Dirk Zingler said: "We are deeply shocked and incredibly sad. Our sincere condolences to the family."
Lewandowski was joint head coach of Leverkusen from 2012 to 2013, and was briefly in sole charge in 2014.