The Los Angeles County coroner's office says 18-year-old Michael Blosil's death was being investigated as a suicide. An official cause of death is pending results of drug testing.
Police have said someone jumped from a downtown apartment building Friday. Friends and witnesses later said the person was Blosil.
The apartment is used by students at the nearby Fashion Institute of Design and Merchandising, where Blosil studied apparel manufacturing.
A grief-stricken Osmond released a statement to ET's Web site saying, "My family and I are devastated and in deep shock by the tragic loss of our dear Michael, and ask that everyone respect out privacy during this difficult time."
Osmond and her brother canceled their Las Vegas shows until March 9.