Australian 1970 murders Five-year-old Susan and seven-year-old Judith MacKay & Marilyn Wallman

Mackay sisters

Five-year-old Susan and seven-year-old Judith MacKay disappeared on the morning of Wednesday, 26 August 1970 from a school bus stop 200 metres (660 ft) from their home in the Townsville suburb of Aitkenvale less than 10 minutes after leaving home. A search for the missing girls was mounted after they failed to return home after school and continued until the girls' bodies were found on Friday in the dry bed of Antill Creek, 25 km (16 mi) south-west of Townsville. Susan was found first and a trail of footprints from her body led searchers 70 metres (230 ft) to where Judith's body lay. It was speculated that Judith had fled while Susan was being killed and had then been run down. A post-mortem revealed that Susan had been raped, strangled and stabbed three times in the chest, possibly after death. Judith had also been raped and stabbed three times in the chest but cause of death was determined to be asphyxiation by sand. Their school uniforms, straw hats and shoes were beside them, with each shoe containing a neatly folded sock while their uniforms were folded neatly inside their schoolbags.[4] The community was outraged, with one policeman stating that he wouldn't go home until they caught the killer. The officer slept at the Townsville police station while his wife brought him food and clean clothing. He died of a heart attack two weeks later.[5] Police initially declined to post a reward but after interviewing more than 6,000 men who lived in the area and having no progress in the investigation, posted a reward of $10,000 (2011: $101,500) with an offer of a pardon for any accomplice who came forward.[6]

One witness saw the girls talking to a man in a car at the bus stop at 8:10am.[5] Just after 11am a car pulled into a service station at Ayr, 85 km (53 mi) south of Townsville and the driver bought $3 (around 25 litre/ 5 gll) of petrol. The two girls were in the car and the station attendant, Jean Thwaite, recalled the younger girl saying "Are we there yet?" followed by the older girl asking the driver, "When are you taking us to mummy? You promised to take us to mummy." Not long after, Neil Lunney, a soldier recently returned from Vietnam, spoke to a driver who had cut him off. Lunney stated that he saw two girls in Aitkenvale school uniforms in the vehicle and that the driver appeared to be trying to avoid being seen. The evidence given by the station attendant and Lunney were both rejected as unreliable as, in contrast to all the other witnesses who identified the car as "looking like a Holden", they had both identified the car as a Vauxhall and neither were questioned "in depth". Several witnesses reported the girls being driven around in a car. Two witnesses later reported seeing a man walking towards a car from the direction of the murder scene around 1pm that day.[5][7]
Identification of the vehicle and suspect

Several witnesses claimed the car looked like a Holden EH. Two witnesses said it was a blue Vauxhall Victor, a very uncommon car at the time. A car seen parked near the murder scene was described as an earlier model Holden (possibly a Holden FJ). Despite the various descriptions of the vehicle, the two witnesses who saw the children inside the car gave matching descriptions of the driver; with him having high cheekbones, narrow skull, short dark hair and, as one put it, "Mickey Mouse ears", and both were in agreement that the vehicle had a driver's door that was a different colour from the rest of the vehicle. One of these was to eventually be a key witness at the trial as he identified Brown as the driver with two young passengers that he had argued with over erratic driving that day. Although 28 years had passed, Brown's appearance had barely changed and he was still very much recognisable as the same person when compared to photographs of him taken in the 1970s. This would be an important factor in identifying him as matching the sketch of the suspect in the Beaumont and Adelaide Oval abductions.

Inexplicably, the two witnesses who said the vehicle was a Vauxhall, later changed their minds and signed statements that the vehicle may have been an FJ Holden. The Police, believing the car seen parked near the murder scene was the offender's, concentrated on finding the vehicle rather than the driver, no sketch or photofit picture of the suspect was ever released and, despite evidence from the witness who refueled the car that the petrol cap was on the left side which ruled out the vehicle being a Holden, the media only ran pictures of FJ Holdens.[5]

Police were unable to locate the car at the time and the murders remained unsolved. Arthur Brown, who matched the suspects description and owned a blue Vauxhall Victor with an odd coloured drivers door, was never a suspect in the original police investigation. The evidence given by the two witnesses who identified the car as a Vauxhall was rejected as unreliable solely due to the belief held by police that the car was a Holden. They were never questioned in depth which police later admitted hindered investigations as both were the only witnesses to speak to the suspect while the girls were in the car.[7]

The Mackay family moved to Toowoomba several months after the murders.
Suspect for Mackay murders

In 1998, a cousin of Brown’s wife who was now living in Perth, Western Australia, who had been one of Brown’s victims and also had suspicions about his involvement with the MacKay sisters, decided to phone Crimestoppers after they aired a program on the case.

Sergeant David Hickey of the Queensland homicide squad, who was conducting the cold case review of the MacKay murders, returned the call three days later. The ensuing months of investigations by Detectives David Hickey and Brendan Rook, including interviewing other family members resulted in 45 cases against Brown relating to pedophilia and circumstantial evidence linking him to the MacKay murders. Investigations continued and evidence accumulated. Brown, who had been working as a carpenter at the MacKay sisters' school at the time, had been obsessed by the case, falsely claiming he knew the girls' father and two weeks after the murders he had offered to take two of his wife’s cousins to view the murder site. He had replaced the odd-coloured door from his blue Vauxhall Victor, buried it, then later dug it up and took it to the rubbish tip explaining to his family he did it because he didn't want anyone interviewing or annoying him. Many of his victims were taken to Antill Creek to be molested and one instance was only 20 metres (66 ft) from where the girls' bodies were found.[2]

Brown had twice previously confessed to the murders.

For more than four decades, police and heartbroken family members have been asking, who murdered Marilyn Wallman and what happened to her when she vanished on her way to school?
Marilyn was just 14 years old when she disappeared while riding her bike to a bus stop near her home in Mackay on March 21, 1972.
She'd set out on the journey slightly ahead of her brothers, who have been left shattered by their sister's death and haunted by the thoughts of what they could have done to help find her killer.

"We were probably about 10 minutes behind her on the bikes and by the time we got over the hill on the way down to where we parked our bikes we found Marilyn's bike on the side of the road," Marilyn's youngest brother Rex told A Current Affair in an exclusive interview.
With Marilyn's bike abandoned and her backpack lying beside the road, the boys knew something wasn't right.
Rex and his older brother David called out Marilyn's name before David headed back to the family house to alert their mother

Two years after Marilyn vanished, bone fragments were found in a field beside a creek, 40 kilometres away from where she disappeared.
While detectives were convinced the fragments belonged to Marilyn, it took another 40 years before technology improved enough for DNA testing to confirm it was the missing schoolgirl.
Finally the Wallmans could lay Marilyn to rest, but now they say her killer must be tracked down.

ref
https://www.9news.com.au/national/marilyn-wallman-cold-case-family-answers-reward/39cf1c45-cfc0-48de-bd65-64af431555e9