Gary Jones was well-educated, from a wealthy family and had a good job.
But in 1990 the 27-year-old accountant walked out of his office at Alexandria, never to be seen again.
Now the police, the coroner and solicitors handling his mother's estate worth millions of dollars want to know whether he is dead or alive.
His mother, Merrillee Jones from Woollahra, left a DNA sample stored in case her long-lost son came forward, and to prevent any imposters from getting their hands on her wealth.
Mrs Jones died in 2005, aged 66, and her son is the sole beneficiary of the estate.
"It is an intriguing case," said Detective Senior Constable Adnan Daye.
"Mr Jones was last seen at his place of employment in Mandible St, Alexandria, on November 9, 1990.
"His parents reported him missing to the local police station and he has not been seen since. Mr Jones has no brothers or sisters and now the estate, which is sizeable, is with solicitors."
The Daily Telegraph has learned that at the time of his disappearance Mr Jones was facing criminal charges relating to the embezzlement of a large amount of money.
Police would not comment on whether this had anything to do with his disappearance. "We are investigating everything we can: financial records, former employees and any of his associates," Sen Constable Daye said.
Police have reopened the case at the request of the NSW coroner.
At the time he went missing police believed he may have travelled to Western Australia to avoid facing court.
In 1990, police said Mr Jones was living in Rockdale and was not in a relationship.
His former wife, who lives in country NSW, has been informed of the reopening of the investigation into Mr Jones' case.
A police statement said family members believed he may still be alive.
Solicitor Gerard Basha, of Bartier Perry, said he could not comment on any matters regarding Mrs Jones' estate.
When Mr Jones disappeared, he was described as being of Caucasian appearance, 178cm tall, thin build with light brown hair and blue eyes. He would now be 48.
Anyone with information should contact Redfern detectives on 8303 5199 or Crime Stoppers on 1800 333 000.