The body of Meaghan Louise Rose was found at the base of Point Cartwright Cliffs at Mooloolaba on July 18, 1997.

The 25-year-old’s car was found abandoned at the top of the cliff and police initially ruled her death to be not suspicious.

In 2009, the investigation was reopened but her murder remains unsolved.

Police on Tuesday announced the $500,000 reward for information to finally bring her killer to justice.

Ms Rose had moved from Victoria to Queensland with her partner, who was more than 20 years older than her. The couple moved to the Sunshine Coast with the man’s young son.

Once there, her partner took out a life insurance policy for Ms Rose containing a clause it had to run for 13 months before coverage applied in the case of suicide.

Ms Rose was found dead at the base of the cliff in Maroochydore 13 months and three days after the policy had been taken out, with her partner later claiming the $203,000 payout.

“We do believe that with public assistance, irrespective of the passage of time, this crime can be solved,” Detective Senior Sergeant Tara Kentwell said.

“Offenders can be brought to justice and we can provide some closure to Megan’s family and friends.”

Ms Rose was one of four siblings – her father has since died and her mother suffers dementia.

“From day one, we never believed this was suicide,” sister Fiona said on Tuesday.

“At the time of her death, just 25 years of age, she had bought her first car.

“She bought her first home and she moved interstate to a place where she always wanted to be.”

Ms Rose told friends and family in the days before her death her relationship was over and she intended to leave.

For decades, Ms Rose’s family clung to the hope of justice, each holding a theory about what happened to their sister.

“We saw the difference in Megan in the 10 months that she had been up here … her demeanour had changed,” Fiona said.

“It’s hard to explain because she was such a bubbly person. She was happy-go-lucky … but she changed.

“It was like she couldn’t talk sometimes.”

Det Kentwell said witnesses would be re-interviewed as police appealed for the public to help.

“We ask if anyone has any information, no matter how small or irrelevant they think it might be, to contact Crime Stoppers nationally,” she said.

“It is never too late to come forward, relationships and loyalties change.”

Anyone with information about the death of Ms Rose is urged to contact police or Crime Stoppers.