The guests at the Cecil Hotel in downtown Los Angeles were concerned about the water. There was weak pressure in the bathroom taps and showers, and a flood in one of the rooms on the fourth floor. “The water did have a funny taste,” said a British guest, Sabrina Baugh. “When you turned the tap on, the water was coming black first for two seconds and then it was going back to normal.” Baugh and her husband had been staying at the Cecil for over a week. “We thought it was just the way it was here,” she later told CNN.

But when one of the Baugh’s fellow residents complained on Tuesday, a maintenance worker was sent to investigate, and in one of the four large, metal water towers on the roof, he made a gruesome discovery: the body of a young woman, lying at the bottom of the tank. The body was soon identified as that of 21-year-old Elisa Lam, a Canadian student, who had been missing for three weeks. The cause of death, said LAPD Sergeant Rudy Lopez, remained uncertain. Foul play had not been ruled out, nor had the possibility of “a very, very strange accident”.

Lam, who arrived in California from Vancouver on 26 January, was last seen acting strangely on CCTV footage from the a hotel lift on 31 January. In the clip, she presses buttons for multiple floors, peers furtively into the corridor, and then retreats to the corner of the elevator as if hiding. Bernard Diaz, 89, a tenant of the Cecil’s third floor for 32 years, told the Los Angeles Times he’d heard a “tremendous” racket from the floor above on the night Lam disappeared. Police said the only routes to the roof where her body was found were via a fire escape, or a locked, alarmed door accessible only to hotel staff.

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The Cecil has a dark past. Opened in 1927 in what was then a thriving neighbourhood, its fortunes declined along with the rest of downtown Los Angeles. Chris Nichols, an associate editor at Los Angeles magazine, told KPCC that the hotel was the scene of more than one murder in its first decade, “and a woman jumped out a window in the ‘60s”.

Thanks to its tumbling room rates, the hotel began to attract those clinging to the lower rungs of society. Richard Ramirez, known as the “Night Stalker”, reportedly stayed on the 14th floor in the mid-1980s, when he murdered at least 14 people. Austrian serial murderer Jack Unterweger, who was later convicted of killing 11 prostitutes in Europe and the US, stayed at the Cecil while writing an article for an Austrian magazine about crime and prostitution in California. He is thought to have killed at least three of his victims during that time.

The hotel came under new ownership in 2007, but, despite its multi-million dollar makeover, the LAPD say officers are often called to the Cecil to deal with drugs and domestic abuse offences. Much of downtown LA has been regenerated, but the hotel still sits mere yards from the notorious “Skid Row” neighbourhood. Following the grim discovery on Tuesday, and despite the management’s offer to put them up elsewhere, 11 of the Cecil’s residents chose to stay put. Rooms start at $65 per night.