More testing must be done to determine the cause of death of a 21-year-old Canadian tourist whose body was found wedged in a water tank atop a downtown Los Angeles hotel, authorities said Thursday.

An autopsy performed Thursday didn't provide definitive answers into whether Elisa Lam was killed or if she fell victim to a bizarre accident.

A spokesperson for the coroner's office told CBC News that toxicology results would take six to eight weeks.

Lam's body was found Tuesday in a water cistern atop the downtown Cecil Hotel. Police have called her death suspicious.

The cisterns are on a platform at least three metres above the roof.

To get to the tanks, someone would have to go to the top floor then take a staircase with a locked door and emergency alarm preventing roof access. Another ladder would have to be taken to the platform and a person would have to climb the side of the tank.

Guest complaints about low water pressure prompted a maintenance worker to make the gruesome discovery.

Before she died, hotel surveillance footage showed her inside an elevator pushing buttons and sticking her head out the doors, looking in both directions.

Hotel water tested

Meanwhile, water tested from the hotel didn't contain any live bacteria that would cause illness.

Although county health officials issued a do-not-drink order, the results that came back Thursday indicated the water was safe from a "microbiological standpoint," said Angelo Bellomo, the county's director of environmental health.

"We can't say what the quality of the water was prior to the samples," taken Tuesday, Bellomo said. "We can only say that the water met the standard at the time it was sampled."

Chlorine in the water likely killed any bacteria in the tank where Lam's body was found, Bellomo said. Two standard water tests were performed and samples were taken from throughout the hotel.

Bellomo said the hotel has retained a consultant who submitted a plan to sanitize the water lines that will be retested before they are put back into operation. Only water for toilets is flowing for hotel guests currently.

Friendly person

Lam, of Vancouver, British Columbia, travelled alone to Los Angeles on Jan. 26 and was last seen five days later by workers at the 600-room hotel near Skid Row. She intended to travel to Santa Cruz, about 560 kilometres north of Los Angeles.

High school classmate Alex Ristea, of Vancouver, called Lam's death shocking and said she was one of the friendliest people he knew.

"This is the last person I expect out of all my friends to have something like this happen to her," Ristea said.

University of British Columbia spokesman Randy Schmidt confirmed that Lam had attended summer school at the university, but she was not registered for the current session.

Earlier reports indicated she was intending to graduate in 2016.

Ristea said he believes Lam had just gone to California for a holiday, saying she had posted pictures on Facebook from tourist locations such as the San Diego Zoo.

Reached by phone, a man who confirmed that it was Lam's home said he was busy and hung up when asked to speak about her. A woman reached later at the same number, when told it was a reporter calling, also hung up after saying, "Sorry."

Historic hotel

The 600-room Cecil Hotel was built in the 1920s and refurbished several years ago. It charges $65 a night.

The hotel is on Main Street in a part of downtown where efforts at gentrification often conflicts with homelessness and crime. It had once been the occasional home of infamous serial killers such as Richard Ramirez, known as the Night Stalker, and Austrian prison author Jack Unterweger, who was convicted of murdering nine prostitutes in Europe and the U.S., the Los Angeles Times reported.