LOS ANGELES (KTLA) — More testing is need to determine the cause of death of a 21-year-old Canadian tourist whose body was found in a water tank atop a downtown hotel.

Los Angeles County coroner’s spokesman Ed Winter said on Thursday that the autopsy on Elisa Lam was completed.

He would not say whether the medical examination found visible signs of trauma on the body.

Winter said that toxicology tests will determine if Lam was taking medication or another substance at the time of her death, and, if so, whether it was at therapeutic levels. He did not elaborate.

He also would not comment on whether coroner’s investigators had determined how Lam got into the water tank or how long she had been there.

Lam’s body was found on Tuesday in a water cistern at the Cecil Hotel by a maintenance worker who was checking out complaints about low water pressure.

Water tested from the hotel didn’t contain any live bacteria that would cause illness, the L.A. County Health Department said Thursday.

A do-not-drink order implemented Tuesday was expected to be in place through the weekend until officials determine the water is suitable for drinking.

Officials tested for disease-causing coliforms at different places inside the 15-story hotel.

“The tests came back negative, meaning that if they were in the water they are no longer viable,” said Angelo Bellomo, director of environmental health.

Chlorine in the water likely killed any bacteria in the tank where Lam’s body was found, Bellomo said.

The Cecil Hotel is expected to drain and flush its tanks and water lines before sanitizing them, which could take two or three days.

The Department of Public Health will then conduct another series of tests before deeming the water safe to drink.

Lam traveled to California from Vancouver on Jan. 26, and she was last seen at the hotel on Jan. 31.

Surveillance video from that day shows Lam inside an elevator. She presses the buttons for multiple floors, and at one point gets out and is waving her arms.

It’s not known why Lam was visiting California, but it’s believed that her final destination was Santa Cruz.

LAPD homicide detectives are now trying to determine whether foul play was involved in Lam’s death or if it might have been an accident.

Police said they searched the hotel with dogs when Lam went missing, but they didn’t know if the tanks were examined.

The only ways to get to the roof are via a locked door that only employees have access to and a fire escape.

Police said that the door has an alarm system that notifies the hotel if someone is on the roof.