A spokesperson for the Erfurt prosecutors’ office confirmed a report first aired on German radio that the woman, 20, had left the Sophien and Hufeland hospital on December 22 with a doctor’s permission. When she did not return, the hospital informed the police and hospital staff began searching the premises for the woman, without success.

The guard who found the woman told investigators he had noticed nothing out of the ordinary when he checked the toilet during a shift on Christmas Eve. But another guard later told police he had noticed the door to the lavatory in question was locked on that night, although he did not try to open it. The disabled toilet where the woman was found is located in a part of the facility that was not used over the Christmas holidays.

“It could well be that the woman had been in the toilet since the 25th,” Annette Schmitt, a spokesperson for the Erfurt prosecutors’ office, told the online edition of Die Welt newspaper.

So far, there is no evidence of external injuries, although Schmitt added that the condition of the body had deteriorated by the time of her discovery. An autopsy to try to determine the cause of death will be carried out on Tuesday.

Hospital officials said the woman had been undergoing treatment at the hospital for several weeks and that an intensive search was undertaken when she did not return from her approved outing. The hospital does not know when she returned, although she did purchase two bottles of alcohol on the day she left, which were found by her body. It is unclear how the woman was able to return to the facility unnoticed. Patients are supposed to be signed in and out.

“There is no 100 percent security when treating the mentally ill,” hospital director Hubertus Jaeger told Die Welt. “And thankfully, psychiatric patients these days aren’t kept under lock and key.”