A coroner has lashed NSW Police Force for long-standing, significant deficiencies in missing person investigations, including a three-decade delay in identifying what happened to 17-year-old girl Ursula Barwick.
Derek Lee's comments came as he closed an inquiry into the disappearances of Ursula and three other people who went missing between 1987 and 2007.
"Overall, the NSWPF investigation into the report of Ursula having gone missing was inadequate (and) ineffective," Mr Lee said on Tuesday.
"(It) occasioned further and unnecessary trauma upon Ursula's family members beyond that which families ordinarily experience when a loved one goes missing in sudden and unexplained circumstances.
"In many ways, the investigation reflects a number of significant and systemic deficiencies associated with missing person investigations more broadly, and that have persisted for over three decades."
Ursula died in a car crash in southern NSW weeks after she was reported missing in September 1987.
But it took until 2016 for police to be sure she was the woman identified by crash investigators as "Jessica Pearce" and given a destitute's burial in western Sydney shortly after the crash.
Searches for her final resting place at an Emu Plains burial site have been inconclusive.
"She deserved better than that. Everything was there in front of them," stepmother Elizabeth Barwick told the inquest in February.
Among the issues, Mr Lee said police minimised the significance of the teen's disappearance in the early days and apparently treated her as "just another runaway".
Similarly, police took 28 years to cross-reference remains located in Little Bay in November 1990 to Gary Jones, who was reported missing 15 days earlier.
The remains were given a destitute burial in 1992 and Mr Lee said it was "devastating" to know an opportunity existed to provide certainty to Gary's mother Merrilee before her death in 2005.
Another case involved police incorrectly marking a missing person as found without proper verification of that fact.
The force has since conceded its investigations of the four cases involved "substantial" failings and a general lack of oversight at local and state levels.
Mr Lee said several reviews were conducted into the Missing Persons Unit from 2008 onwards but little was done to address the systemic issues identified until 2018, when the entire unit was disbanded.
The role and function of the MPU had been ill-defined and misunderstood by local police officers, leading to a lack of ownership of cases.
Inadequate resourcing left MPU officers largely performing superficial tasks such as proof-of-life checks rather than meaningfully advanced investigations.
A new agency has since been established and revamped procedures issued to the force's 21,000 employees.
Missing persons coordinators have been appointed for local police districts while each of the 30-odd missing person reports recorded in NSW each day is now reviewed within a day by the new Missing Persons Registry.
Still, Mr Lee said there was scope for improvement.
He made five recommendations, including the making of a formal agreement between police and the state's forensic health unit concerning unidentified remains.