According to a TMZ report, around 9 p.m. Blosil, the 18-year-old son of entertainer Marie Osmond, sent a text to the friend, a fellow resident of the Met apartment building with whom he had planned to spend time that night.
When she arrived at his eighth-floor apartment, Blosil's roommates – who hadn't known anything was wrong – let her in. They recovered the note, in which Blosil, a student at the nearby Fashion Institute of Design and Merchandising majoring in apparel manufacturing, had written about being incredibly unhappy.
He also talked about "things he would be doing for the very last time," the TMZ report says, and called the woman "his only good friend in L.A."
Within a few minutes of reading the note, Blosil's friend and roommates heard the sound of approaching sirens.
The Los Angeles City Fire Department received a 911 call reporting the suicide at 9:24 p.m. According to Fire Dept. spokesman Shawn Lenske, "We were dispatched ... for an extreme fall, which is categorized as greater than 30 feet. The person had fallen from a 15-story building. The person was [dead on arrival]."
Lenske also said, "I have no information on whether drugs or alcohol were involved ... The investigation is ongoing by the coroner's and LAPD."
Immediately as word of what happened had spread, students from the nearby Fashion Institute of Design and Merchandising began gathering in the lobby of the apartment building. From the street, Blosil's body had been covered with a white sheet.
"Everyone was in shock," student Tammy Nguyen told the Los Angeles Times.
The next day, a few mourners paid quiet tribute to Blosil, braving the rain to leave a few flowers near the building on Flower Street.
The coroner's office confirmed to PEOPLE late Saturday that an autopsy would take place on Sunday.
With reporting by KEN LEE and BLAINE ZUCKERMAN