The U.S. military is investigating an American soldier accused of raping a woman in Okinawa, an army official said.

An army-appointed investigator began the military equivalent of a pretrial probe Monday into the allegations against a 25-year-old specialist assigned to Kadena Air Base on Okinawa, army spokeswoman Amanda Kraus said.

The soldier, accused of assaulting the woman in February in a hotel room, is restricted to the base but is not facing formal charges on any of the allegations, she said.

In May, prosecutors in Okinawa dismissed charges against the soldier after finding insufficient evidence. Army investigators have pursued the case since.

The next step in the military legal process is a preliminary hearing by an independent officer, she said.

The army has 120 days to decide whether to formally press all or part of the charges.