IN part one of The Chronicle's Unsolved Crime series, we revisit the brutal 1989 murder of Toowoomba teenager Annette Mason and the investigation that is ongoing today.

IT is widely believed a woman living in Melbourne holds the vital key that could lead to the arrest of the man authorities believe is responsible for the murder of teenager Annette Jane Mason.

She is understood to have intimate knowledge of the murder but is so fearful of retribution she has remained silent for nearly two decades.

The brutal, vicious and senseless murder on November 19, 1989 is Toowoomba's only active cold case murder investigation.

The 15-year-old's badly beaten body was found partly naked and concealed underneath a doona in the sunroom of a house she shared with two other women at 131 Anzac Ave.

She had only moved into the house two weeks earlier.

Toowoomba's worst unsolved crimes: Annette Mason: The 1989 killing of teen Annette Jane Mason is Toowoomba's only active cold case murder investigation.

It is believed Annette was murdered sometime between 5am and 7am before her body was discovered around 2.10pm.

An autopsy revealed she died from extensive head injuries and police believe a piece of timber found in the laundry could have been the murder weapon.

Pathology reports conducted at the time did not reveal whether Annette had been sexually assaulted.

But the passage of time has not done anything to bring an end to the nightmare for her family.

Annette's father, Andrew Mason, talking to The Chronicle from his home in Newcastle, said it had not been easy in the years since Annette's murder.

"She was a good kid. When it happened it was all a haze," he said.

"I was dumbfounded that it happened.

"It was not easy . . . I was not really good for a long while after that."

Annette Mason.

I think it is time for people to come forward and tell what they know.

Mr Mason said he believed the police investigation was thorough and understood they had a suspect in mind.

"They could never pin it on him," he said

"When his mother died the alibi died with her.

"It (the case) does not seem to be going anywhere are the moment, but if the police get anything they contact me before it goes to the paper or anywhere else."

Mr Mason said he hung on to the hope that one day his daughter's killer would be brought to justice.

The petition calling on Attorney-General Yvette D'ath to act and order a coronial inquest into the murder of Annette Jane Mason can be found here.

RELATED: Mother of murdered teen still seeks closure

He said it needed to happen for his peace of mind.

"I think it is time for people to come forward and tell what they know," he said.

"There are a couple of people out there that know what happened to Annette.

"If they can get the lady in Melbourne to open up, then I would say to her, get it out in the open so we can get it finished with.

"She must know what happened and we are all pretty sure we know the man who did it, but we just need her evidence to prove it.

"We just need closure."

SEARCH: A detective conducts a search on the murder site. Bev Lacey

There was a group of people living in Toowoomba who have knowledge of what happened to Annette.

Police investigations at the time revealed Annette had been out with friends in Toowoomba the previous night and was seen at several parties before heading to the Norville Hotel in Russell St.

She was later refused entry to Rumours International nightclub on Ruthven St and decided to call it a night.

The teenager was last seen alive at 3.30am when she arrived home in a taxi.

RELATED: Annette's father holds on to hope

Witnesses who gave evidence at a secret Queensland Crime Commission hearing in 1999 said they saw a man chasing a person fitting Annette's description along Anzac Ave not far from her home a short time later.

Queensland Crime Commission investigators took the unusual step the following year to reveal they were sifting through a "web of lies" they claim had been woven to protect her killer.

Investigators said they believed Annette knew her killer, but there could have been more than one person involved.

Police involved in the murder hunt. The Chronicle Archives

But a 1991 coronial inquest into her death held over four days in Toowoomba delivered an open finding.

Coroner Ross Woodford heard evidence from 27 witnesses, read 147 statements and the 72-page police report but found there was insufficient evidence to commit any one person to trial.

The inquest heard there were initially up to 13 suspects in Annette's murder.

Police believe a person of interest, whose name was suppressed at the inquest, was highly intoxicated and could have gone to Annette's house after meeting her earlier in town.

RELATED: Woman told friend she knew who killed teen, court hears

Police believe one possible scenario was the man, who was well known to them, became violent towards her after she may have refused his advances.

Police believe Annette then fled the house because of the man's violent behaviour before returning a short time later.

It was one possible scenario police investigated at the time, but there were others that were never made public and that The Chronicle is prevented from revealing.

The person of interest was later jailed for unrelated armed robbery offences.

Police search for clues in the Annette Mason murder mystery. The Chronicle Archives

It has bothered me every day since I retired that this case has not been solved

While inside prison, he bashed another prisoner to death and was later sentenced to life behind bars.

He has since been released on parole and is believed to be living with his sister in the Ipswich region.

Retired Toowoomba Police detective Brian Tighe, who spent 13 years investigating Annette's murder, said the case needed to be revisited.

RELATED: Teen's murder haunts retired police officer

He said if a coroner were to investigate the murder again today he had no doubt a number of people still alive would face criminal charges.

"I maintain a keen interest in the Annette Mason murder following the open findings of the 1991 coronial inquest," he said.

"Much valuable information was gathered up until my retirement.

"Despite several public appeals for assistance, it appears no progress in the case has been made."

Retired Toowoomba Police detective Brian Tighe, Scott Fletcher

We still believe there are people in the community who can offer further assistance in this case and we do appeal for them to come forward and provide that assistance to us.

Mr Tighe, who retired in 2001, said Annette's murder and the fact it remained unsolved still haunted him to this day.

"It has bothered me every day since I retired that this case has not been solved," he said.

"Any detective worth their salt does not want to see a case go unsolved, especially one that is very solvable.

RELATED: No increase to reward for information on Annette's murder

"I honestly believe this case could be solved if the inquest was re-opened.

"I feel that all new evidence and information that I gathered should be reviewed at a coronial inquest without delay.

"There was a group of people living in Toowoomba who have knowledge of what happened to Annette.

"If they (police) want to solve this the evidence is already there and I have no doubt whatsoever they could get a result."

HISTORIC CRIME: Annette Mason was murdered on November 21, 1989. Contributed

He said indemnity from prosecution would also be recommended for any accomplice, not being the person who actually committed the crime, who provided such information.

"Annette's unfortunate case remains an open cold case investigation," he said

"We undertook a significant review of that case in 2011.

RELATED: My murdered daughter forgotten, inquest rejected

"We still believe there are people in the community who can offer further assistance in this case and we do appeal for them to come forward and provide that assistance to us."

The house where Miss Mason was murdered in Anzac Ave, near the corner of Goode St was removed in July 2000, taking away the last visible reminder of the sickening crime.

The petition calling on Attorney-General Yvette D'ath to act and order a coronial inquest into the murder of Annette Jane Mason can be found here.

Anyone with any information surrounding Annette Jane Mason's murder in Toowoomba on November 19, 1989 is urged to phone Crime Stoppers on 1800 333 000.