A toxicology report on Khuteja Banoo Imam, who was reported missing in January then found dead on the shores of Glenbrook in February, did not help Douglas County authorities in determining the cause of her death.
"We can't necessarily rule it as a suicide. We can't show it as a homicide or even for that matter accidental," said Lt. Mike Biaggini.
"What is basically spelled out is we have no solid proof as to being able to make a call one way or another at this point in time."
Biaggini said the investigation will remain open but will be considered a cold case.
Imam, 64, was reported missing in January when she did not return after she drove away from the Crystal Range Motel, which she co-owned, in her green 1999 Honda CRV.
The vehicle was found parked at Camp Richardson days after her disappearance, but Imam was found about 15 miles away and approximately three weeks after she was reported missing Jan. 13.
Typically, bodies in Lake Tahoe never surface because cold water thwarts decomposition. Biaggini said there are indications Imam was in Lake Tahoe in the three weeks she was missing, and water was found in her stomach.
DNA tests were used for identification purposes.
An autopsy and other investigative methods proved difficult in collecting information since Imam's body was close to shore.
Biaggini said Imam's body had markings left by animals, making finding signs of other wounds impossible.
The toxicology report did reveal traces of alcohol, Biaggini said. The amount could have been produced during the decomposition period, Biaggini added.
Tips collected through the investigation indicated Imam might have taken her own life, but Biaggini declined to divulge the details.