LOS ANGELES (AFP) - The body of a 21-year-old Canadian tourist was found in a water tank on the roof of a Los Angeles hotel three weeks after she went missing, police said on Wednesday, calling the death suspicious.

The corpse was found on Tuesday after hotel guests complained of low water pressure. It was suspected to be that of Elisa Lam, but police only confirmed her identity after concluding that "body markings" matched hers.

Lam, from Vancouver and traveling alone, had been missing since late last month when she stopped making daily contact with her parents. Security footage from an elevator camera showed her acting strangely.

Management at the Cecil Hotel, in the skid row area of downtown Los Angeles, said rooftop access doors were locked and had alarms, but four water storage tanks there were not locked.

"We're not ruling out foul play," LA Police Department spokesman Rudy Lopez told the LA Times, noting that the location of the remains "makes it suspicious."

Police were investigating Lam's movements after she arrived in Los Angeles on Jan 26, he said.