The state prosecution service in Munich said it had launched an investigation into an American who may have caused the surge in cases.
"There is an investigation for possible assault through negligence," said Andrea Meyer, from the state prosecutor's office.
The unnamed person, who had recently returned to Bavaria following a holiday abroad, chose to socialize despite having Covid-19 symptoms, according to Stephan Scharf, press officer at Garmisch-Partenkirchen District Administrator's Office.
Sharf said the individual took a coronavirus test and was told to stay indoors until they received their results, but did not do so.
The person subsequently tested positive and is now in quarantine, Scharf said. It's unclear which countries they may have visited, but the district administrator's office says it was not the US.
Sharp jump in cases
The individual works at Edelweiss Lodge, a US Armed Forces Recreation Center Resort in Garmisch-Partenkirchen, operated by the US Army and frequented by military personnel, Scharf said.
In the wake of the incident, 24 people at the lodge tested positive for coronavirus, and Garmisch-Partenkirchen has recorded a sharp jump in cases, with 33 reported on September 11 alone.