Elisa Lam, 21, of Vancouver, was traveling by herself and staying at The Cecil Hotel at 640 S. Main St. on the edge of downtown Los Angeles' skid row.
Investigators said Lam called her parents every day until Jan. 31. Her parents haven't heard from her since.
A desk clerk and café hostess at the hotel said they remember seeing Lam, but didn't remember seeing her with anyone. The last people known to have seen Lam are hotel staff.
Lam was unfamiliar with the area in which the hotel is located and was traveling on a budget.
"I don't believe she had any idea that might that might be a location to be concerned about," said Lt. Walter Teague of the Los Angeles Police Department's Robbery-Homicide Division.
Because Lam is from Canada, the International Criminal Police Organization has become involved in her search.