Police Offer $500,000 Reward in 1997 Bowen Cold Case Murder

Police have put up a $500,000 reward for information about the unsolved murder of a 50-year-old woman in north Queensland, three decades ago.

Dianne Mary Angwin was fatally stabbed in the neck inside her unit in Bowen on December 2, 1997.

Police believe Ms Angwin was woken during the night by an unknown male assailant, where she was then fatally stabbed.

No one has ever been charged over her murder.

Ms Angwin was last seen socialising at the Bowen Bowls Club with her friend and housemate, Edith "Edie" Lay, the night of her alleged murder.

Detective Senior Sergeant Tara Kentwell from the Cold Case Investigations Team said Edie told police she woke in her bed to an unknown man holding a knife to her throat.

"Diane turned and ran from the doorway, the man pursuing her," Detective Senior Sergeant Kentwell said.

Police say they now believe the man was known to Edie, but she concealed that information.

"Police have identified witnesses who Edie confided in, confirming that she did know the identity of the man and that had not told police at the time of the offence as she was scared for her own safety," Sergeant Kentwell said.

The man was interviewed at the time but was never a formal suspect.

"This person will be re-approached as part of our current review."

Police believe Edie may have shared this information with other members of the community before she died in 2002 and are urging those people to come forward.

Ms Angwin was in a relationship with a local married man who had been seen at her flat, according to police.

Ms Angwin's granddaughter, Hayriye Yaman, said the heartbreak over the years had been "incredibly devastating".

"We've never had the chance to meet her, make memories with her, or experience the love and guidance that every grandchild deserves."

Ms Yaman hopes the reward can bring their family much-needed closure.

Investigators will set up a mobile facility in Bowen to interview members of the community, as forensic testing continues.

"New and enhanced forensic testing of exhibits located at the crime scene, including the clothing worn by Dianne at the time, is currently being conducted."

Police had previously offered a $250,000 reward for information and hope the increased reward will encourage people with information to come forward.