On April 20 1934, the Priestly family lived in a first-floor tenement at 61 Urquhart Road, directly above their neighbours the Donalds.
The two households were not on speaking terms, with Agnes and Jeannie, both mothers to young daughters, having fallen out a number of years beforehand.
Eight-year-old Helen Priestly was a quiet girl who was wary of strangers. During her school lunch-break, Agnes had sent her to buy a loaf of bread from a local bakery.
When the little girl did not return that afternoon, Agnes immediately entered a state of panic. A visit to the bakery confirmed that she had indeed bought the bread and she was found not to have returned to school for the rest of her lessons.
A night of searches ensued, with members of the Priestly family, as well as people from across the city joining in an effort to trace the missing child.
It was the next morning that Alexander Porter, who lived across the street, wandered into number 61 while the family prepared to resume the hunt. Near the back door of the house, he found a large, blue sack with two small feet poking out.
Inside was the body of little Helen Priestly.
Once he had told of the find, screams rang out across the block. One of the biggest police operations ever seen in the city soon began, and the public were baying for the blood of the culprit, with large crowds gathering on the street.
Initial inspections of Helen’s injuries suggested that she might have been sexually assaulted, which meant the men in the block were the prime suspects.
Most of them were ruled out promptly, once it was established that they had been at work at the time of the attack. Having probed nearby back-courts and sheds in their search for evidence, cops turned their attention to the Donald household.
After finding red stains which were believed to be blood, Jeannie Donald and her husband, Alexander, were arrested and driven to the police headquarters just off Union Street.
Jeering crowds lined the streets as the van carried the couple, while press photographers from across Scotland assembled to capture what was quickly becoming the biggest story in the country.
After six weeks in custody, Alexander was freed, with detectives convinced he was innocent.
Jeannie, however, became the prime suspect as proof was gathered. Fibres found on the sack matched some of those in her house and hair strands which belonged to her were found at the scene.
Crucially, an autopsy revealed that Helen had not, in fact, been the victim of a sex attack, and that the perpetrator had fabricated injuries to make it seem like the crime had been of a sexual nature.
Jeannie Donald pleaded not guilty at the trial, which began in July at the High Court in Edinburgh.
Her defence was doomed from the beginning, with no witnesses prepared to support her story. The prosecution struck the final blow when scientists confirmed that there were traces of blood on a newspaper, as well as on items around her sink.
After deliberating for 17 minutes, the jury convicted her of the murder. As was customary for a crime of its nature, she was sentenced to death.
She broke down in the courtroom and was carried off screaming while a mob outside celebrated the verdict.
The hanging was scheduled for Craiginches Prison back in Aberdeen on August 13. During the 1930s, appeals on behalf of those sentenced to hang were rarely granted.
However, it was very rare for women to be executed and this would have been firmly on the mind of the Secretary of State for Scotland, who was responsible for judging whether or not to recommend a reprieve for the killer.
The day after her lawyers submitted an appeal, the Secretary wrote to the Lord Provost of Aberdeen confirming that the sentence was to be commuted to life imprisonment.
After Lord Provost Henry Alexander rushed to the prison to deliver the news, Jeannie Donald was escorted to Duke Street Prison in Glasgow. She would spend 10 years behind bars before being released.
The timing of her exit from prison at the height of World War Two meant that there was little reaction from the war-worn public.
She died in 1976, having faded into obscurity after she was freed. Little is known about how the Priestly family picked up the pieces after the tragedy, nor has a clear motive for the killing ever been established.
Helen was buried in Allenvale cemetery. A poem etched on her gravestone remains a poignant reminder of her life and tragic death.
“Grant that her little life
So short here
May unfold itself in thy sight.”