The initial investigation has ruled out the involvement of others in the death of Lt. Col. Joshua Camara, Polish state news agency PAP reported.
According to Col. Bartosz Okoniewski, Deputy Military Prosecutor for the Poznań District Prosecutor's Office, the 45-year-old lieutenant colonel's body was discovered on Tuesday in an apartment close to the US military base Camp Kościuszko in Poznań.
The body has been secured for an autopsy, with preliminary findings suggesting accidental death, Okoniewski said.
"The results of the autopsy, expected this week, are crucial in this case," Okoniewski told reporters.
"Toxicological tests are also significant but tend to take longer," he added.
US broadcaster Fox News reported that the US Army will also conduct its own investigation into the officer's death.
Camara had been serving since June in the V Corps of the US Army as a press officer.
Camp Kościuszko, named after the 18th-century Polish-American independence hero, was established as part of the eastern flank of NATO and is the permanent forward command headquarters for the V Corps.
Under international agreements, the United States has the option to request the takeover of the investigation, but such a request must follow formal procedures.
"So far, there is no information that the American side wants to take over the investigation," Okoniewski said.
(rt/gs)
Source: PAP