Scott's body was discovered Monday at her Manhattan apartment. According to the autopsy results released on Wednesday, the 49-year-old died of hanging.
Police said her assistant found her kneeling with a scarf wrapped around her neck that had been tied to the handle of a French door. There was no suicide note.
Scott had been romantically linked to the Rolling Stones frontman for more than a decade. The Rolling Stones called off their seven-date tour of Australia and New Zealand following Scott's death.
In a Facebook post, Jagger, 70, called Scott his "lover and best friend" and said he will never forget her.
Scott was a renowned stylist and fashion designer whose clothes were worn by celebrities like Nicole Kidman, Angelina Jolie and Penelope Cruz.
Her fashion label had been heavily in debt and was reportedly about to fold.
The Associated Press contributed to this report.
