"The cause and manner of death is pending toxicology results," the Coroner Division of the San Bernardino County Sheriff's Department said in a statement. No other details about the investigation were released Thursday.
On June 28, Lauren "El" Cho was staying with friends, including her ex-boyfriend, at a home on Benmar Trail in Yucca Valley, about 12 miles from Joshua Tree National Park. The friends said she was "upset and presumably walked away from the resort, leaving behind her personal belongings," according to the Sheriff's Department.
Her ex-boyfriend reported her missing about three hours after she disappeared. Investigators have said the ex-boyfriend "indicated she was suffering from mental distress."
Extensive searches by air and ground were conducted, and missing-person flyers with Cho's description and photos were posted throughout the area.
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"We have gone thousands of miles and tirelessly went to gas stations and pasted up flyers in the low desert, the high desert," a friend, Jeff Frost, said. "We went out to San Diego because she said in the week before she disappeared that she just wanted to go to the beach."
On Oct. 10, authorities announced the discovery of human remains in an area described as "rugged terrain of the open desert of Yucca Valley."
Anyone with information about the case is asked to call the Sheriff's Department's dispatch center at (760) 956-5001 or Detective Ables at (760) 366-4175.
The CNN Wire contributed to this report.