Uncovered near the backpack at the Randwick construction site were several bones, which police do not believe belong to the slain 18-year-old, but are being tested to determine if they are human.
Ms van Blanken, a trainee Disney animator, was strangled to death by her ex-boyfriend in November 2003 and her body found seven weeks later in the store room of an eastern suburbs unit block.
Her “intense and obsessive” former boyfriend, cellist William Matheson, was jailed for at least 18 years for her murder in 2006 and will not be eligible until 2022.
“The backpack has been confirmed as belonging to Lyndsay van Blanken, who was murdered in 2003,” a NSW Police spokesman told AAP on Friday.
“Detectives from the State Crime Command’s homicide squad have notified Lyndsay’s family who have requested their privacy be respected at this time.”
Tests on the bones are still being conducted.
“Until we can confirm whether or not they are human it would be unwise to speculate,” the police spokesman said.