The grim discovery was made Tuesday afternoon after military police stormed an apartment block in the city’s Grunwald district, not far from where the U.S. Army V Corps is based.

Deputy District Prosecutor for Military Affairs in Poznań, Colonel Bartosz Okoniewski, told the Epoznań.pl news portal that the soldier was a “senior officer”.

He added that initial findings had ruled out murder and that the investigation was focused on “unintentional manslaughter”.

The results of an autopsy are expected early next week.

Poznań is home to Camp Kościuszko, the first permanent U.S. military base in Poland, and to the U.S. Army Garrison Poland and V Corps' forward headquarters.