This is a very, very odd situation, and they deserve answers and they deserve closure,” an attorney for the Kobayashi family tells PEOPLE

The family of a Hawaii woman who vanished after landing in Los Angeles three weeks ago have expressed frustration with investigators and say they haven’t seen the surveillance footage that shows her walking across the border into Mexico.

Hannah Kobayashi, the Hawaii woman who’s been missing for more than three weeks after arriving in Los Angeles on a flight from Maui, has been declared a voluntary missing person, Los Angeles police said Monday.