Sources within local law enforcement agencies say they are still unsure over events leading to the death of Canadian tourist Elisa Lam. Sources indicate it is still too early to consider the case a homicide.

Elisa Lam, 21, was last seen in the 600-room Cecil Hotel in Los Angeles on 31 January. She was then found, dead, in a water tank in the same hotel.

The body was found by a maintenance worker investigating the cause of low water pressure. Authorities believe Lam travelled to California from Vancouver on 26 January.

An autopsy on Lam's body has been scheduled for Thursday and it remains possible the young woman died of accidental causes. Investigators hope any evidence of trauma will be documented in the post-morterm report.

A Los Angeles Times report adds police are also investigating Lam's hotel room.

Meanwhile video footage released by police last week after Lam went missing raises more questions than answers.

The video, from a CCTV camera in a hotel elevator, shows Lam behaving strangely; she enters the elevator, pushes multiple buttons and then peeps out of the elevator, as if looking for an attacker. She then proceeds to step in and out of the elevator a few times.

Mid-way through the video, Lam is seen standing outside and appears to be talking to herself, while making rather elaborate hand gestures. Nobody else is seen in the video with her. She then exits the elevator and disappears from the camera's view.

The video, available on YouTube, has been extensively commented on, with some believing Lam seems drugged while others say an unidentified hand can been seen, towards the end of the clip, preventing the elevator door from closing.

One user wrote a rather extensive comment: "1:08-1:48 The stalker orders her to hold up her hands, instructs her to repeat pressing the floors in the elevator (in order to act normal). [Between] 1:46 [and] 1:51 she is threatened to step back outside the elevator.

"[Between] 1:51 [and] 2:27 She is ordered to look at the surveillance camera (1:54) and then act like she's stupid/drunk/drugged/crazy (at 2:22 you can see stalker's hand keeping the doors from closing, clearly he wants you to *think* she's crazy) 2:27 and beyond: A tragedy."

Another wrote: "Please don't believe the HAND THEORY at 2.22 it's not a hand it's the angle of her foot turning around...her slipper...look again."

The video, uploaded by MrFrankPreciado, can be viewed here:

READ Missing Canadian Woman Elisa Lam's Death: Cecil Hotel's History Has Serial Killers and Unsolved Murders [VIDEO]

Los Angeles County Coroner spokesman Ed Winter said there is currently no way of knowing how long the body had been inside the tank.

"We did a very thorough search of the hotel," Sgt Rudy Lopez told the LA Times. "But we didn't search every room; we could only do that if we had probable cause that a crime had been committed."

Admission to the terrace of the hotel is restricted, with only employees having access to that part of the building. Apart from that, the fire escape is the only way to get to the roof.

The door to the roof has an alarm system that notifies hotel personnel if someone goes to the roof, Lopez continued.

Clueless tourists staying in the hotel bathed and brushed their teeth with the water from the tank which contained the decomposing body of Lam.

It is yet to be established if the water posed any health danger. A test was conducted on Wednesday by the Los Angeles Public Health Department but the results are yet to be announced.

"The water did have a funny taste," Sabrina Baugh, a British national tourist staying in the same hotel, told CNN. Baugh and her husband used the water for eight days.

"We never thought anything of it," she said. "We thought it was just the way it was here."

However, Baugh did find something very wrong with the shower water.

"The shower was awful," she said, "When you turned the tap on, the water was coming black first for two seconds and then it was going back to normal."

Elisa Lam
Elisa Lam corpse found dumped in hotel water tanks