Hazel Marshall, pictured left in this photograph from the late 1980s, was the love of Dave Johnston’s life. Picture: Anne Stewart

It was 1988 and the lovable Scottish larrikin had found his match in the beautiful Sydneysider. The pair had decided to make Manly their permanent home but first they wanted to get some serious travelling out of their systems.

They decided Dave would take a six-month working holiday in Los Angeles while Hazel made the traditional Aussie pilgrimage to Europe.

The plan was for the couple to reunite in London that December. Tragically, Dave never made the flight.

Hazel would later learn her soulmate had been found dead on a freeway in Palm Springs. Police suspected his massive head injuries were the result of having been thrown from an overpass.

Dave’s sisters, Anne Stewart and Linda Lunn, who lives in Victoria, tried to keep in contact with Hazel, who was “absolutely shattered” by his murder, which remains unsolved.

“Dave and Hazel were the most amazing couple who loved life and each other very much,” Ms Stewart told news.com.au.

“I think she was heartbroken by his death. We all were. It was a massive shock and it left a huge hole in our lives. Nothing was the same ever again.”

Hazel Marshall (right), with Dave Johnston’s sister Linda Lunn (left), who lives in Victoria, in an undated picture.Source:Supplied

From left: Dave Johnston, his late mother Mary, Hazel Marshall, Dave’s brother John who died last year and his wife in a photograph from the late 1980s.Source:Supplied

After decades of “pestering” the Palm Springs police to catch their brother’s killer, Ms Stewart and Ms Lunn finally received some good news: cold case detectives had decided to reopen the case following a review of the evidence.

Now the siblings are on a mission to deliver the good news to Hazel, whom they haven’t seen since 1997, and are struggling to track down. They also need to tell her that investigators want to interview her to get a better idea of what was happening in Dave’s life at the time of his death.

“We have been trying to get justice for our brother for 29 years,” Ms Stewart said.

“And then in August we got word that the police were reopening his case. Our mother passed three years ago without getting justice for her son, who was robbed of his life.

“That’s why we are so desperate to track down his beloved Hazel, so we can give her the news, so we can give her some kind of closure.”

Ms Stewart has flown from her home in Scotland to stay with Ms Lunn in Geelong in a last-ditch effort to find Hazel.

Ms Lunn’s daughter, Jodie Armstrong, who grew up with the story of her uncle’s tragic, unsolved death, has put the feelers out on social media, posting photographs of the young couple on Facebook.

“Can all my friends please share..... Our family is trying to track down Hazel Marshall, she’s around 52yo and was residing in Manly, Sydney the last time we had contact which was around 1997,” Ms Armstrong said in a December 30 post.

“My uncle, Dave Johnston....and Hazel...used to be a couple. Dave was murdered in America 29 years ago and the case remains unsolved. The case is being reopened and investigators are keen to speak with Hazel. Please share to help us find her.”

Madly in love: Hazel and Dave lived together in Manly, Sydney before he was murdered in California during a working holiday.Source:Supplied

The women believe Hazel was a couple of years younger than Dave and estimate she would be aged between 50 and 52 today.

They also recall Hazel might have had family in the southern Sydney suburb of Sylvania Waters.

“From the minute I met Hazel I liked her; my brother had great taste in women,” Ms Stewart told news.com.au.

“I would love to meet her on this trip and give her the news.”

The sisters still know very little about what happened to their brother, who had an enormous circle of friends and was considered an all-round great guy.

At first detectives told them they suspected he was a victim of “mistaken identity”, an idea which never sat well with his family.

“I think it would be pretty hard to mistake Dave for someone else. He was a quite a personality, Scottish, he would have stood out in Palm Springs in those days,” Ms Stewart said.

“The police told us they suspected it was murder, which was very unusual in a low crime area.

“However, we do know that there was a police officer killed in the area a week earlier and that [police] resources were probably taken up by that case and Dave’s took a back seat.”

Do you know Hazel Marshall?

Contact marnie.oneill@news.com.au