The mother and daughter Australia forgot.

The murder of Margaret and Seana Tapp should be etched into our bones.

As Australians, we should all remember the mother-and-daughter killed in their beds in suburban Melbourne in the 1980s. 

The Tapp Murders — like The Beaumont Children and The Easey Street murders — should be an unsolved crime we all know by name. 

And yet it's a case that fell through the cracks in more ways than one.

Listen: To the details of this case on True Crime Conversations. 

It was the winter of 1984 when Margaret and Seana were found dead in their beds in Ferntree Gully, at the foot of the Dandenong Ranges. 

They'd been strangled and the little girl, only nine when she died, had been sexually assaulted. The crime was so horrifying, the detective who was first on the scene went home and wept that evening.

Margaret was a single mum; a nurse, a part-time law student and beloved by many. Seana was a normal, happy little girl who was part of the local Brownie girl guides and adored her dog, a friendly spaniel.

Police had a few decent clues. They found semen at the scene, fibres were found around their necks suggesting a specific rope had been used, and a distinct footprint was lifted. Found in both Margaret's bedroom and the bathroom, the print had been made by a large pair of Dunlop Volleys.

Margaret Tapp. Image: Victoria Police.

Speaking to Mamamia's True Crime Conversations, crime author and Herald Sun journalist Andrew Rule, who has covered this case extensively, says the problem was they couldn't narrow in on a suspect.

While Margaret's ex-husband was quickly cleared, she'd dated other men since the split, including a doctor.

The doctor purchased a house for her to live in rent-free (the home in which she was murdered), and for a while police were investigating this man's wife. She was never actually eliminated from their list of persons of interest, but Rule thinks she was "wrongly" a suspect.

"A ridiculous suspect, but the police were pretty keen on her for a while, and thought she'd had Margaret knocked off by a murdering paedophile... which would strike me as a fairly long shot, that a doctor's widow would employ a hit man who was also an active paedophile who would sexually assault the child," he said.

Seana Tapp was nine when she was murdered. Image: Victoria Police.

Among other potential suspects, there was a relative's boyfriend, who had been at the house earlier that day, a married friend who was teaching her to drive a truck, a troubled teenage boy who lived on the same street, and a former police officer named Ian Cook, who was a friend of her parents and visited the crime scene.

"He was allowed back into the crime scene to retrieve a book or letters or something, and the coppers let him in because he was either still a serving copper or just out of the job. Now that puts him at the crime scene. It means he can get his fingerprints there legitimately, which covers him if his prints are found," said Rule.

When he was later questioned by police, Cook refused to give his fingerprints to police.

Rule also suggests that there may not have been a connection to Margaret at all. He spent a long time looking into a GP from the Dandenong Ranges who was known to have molested several children.

"He would go regularly to that hospital where Margaret worked. He wasn't one of the hospital doctors, but he would go there," he said.

"Another potential thing is Seana was a Brownie and we know looking back on it that Brownies, Scouts... they were full of paedophiles."

There was a man who was wrongly arrested for the crimes in 2008. Prisoner Russell John Gesah was charged with the murders after the semen stain was found to be a DNA match, but police later found out that had been a mistake. There had been a complete bungle in the lab.

Looking at the case 20 years on from the murders, Rule was quick to notice that many of the potential suspects were never properly ruled out.

"In the end, it sort of collapsed under the weight of all these potential suspects that I don't believe were cleared properly back then, and only halfheartedly cleared later... because Margaret's brother Lindsay assured me that he hadn't been cleared by DNA samples until 20 years later. He himself had to be regarded as a suspect, because they had DNA from the scene."

In 2015, investigators reopened the case in a cold case review and a $1 million reward was offered for information that could lead to a conviction. But nothing of note has happened since.

In another cruel development in the case, however, Margaret's other child, Justin Tapp, died before seeing the case reopened. He was just 14 when his mum and sister were murdered, and wasn't home at the time. He had been diagnosed with depression and PTSD, and despite moving to England, struggled to move on from the murders. 

He died in 2014, it's believed from either suicide or alcohol poisoning.

As Rule wrote for The Herald Sun at the time, "Justin Tapp wasn't strangled like his mother and his little sister, Seana. He was slowly poisoned by the horror of what happened to them."

The reason this case hasn't received as much press can be put down to several reasons. The family rarely talked to media and the police developments dried up quickly. It didn't leave journalists much to write about to progress the story.

"Everything just spluttered out. It was awful, and I feel bad that's what happened," Rule told True Crime Conversations. 

"But it wasn't a media conspiracy. It wasn't a police conspiracy... and [also] there's not an appetite for child sex [abuse] stories. They're so awful and abhorrent."

But even Rule admits he was wrong. He himself didn't cover it in detail until 20 years after the fact, and he regrets his part in letting it fall from the headlines.

"After more than 30 years, a murdered mother and her two dead children deserve better," he wrote in 2018. 

Even in 2024, it's one of those stories that he can't shake.

Feature Image: Vic Police.