It's a mystery that has gripped Australia for over 50 years, but new information may shine light on what actually happened to the Beaumont children.

In 1984, supermarket shoppers in Des Moines, Iowa, found something truly shocking in the dairy aisle — milk cartons printed with the faces of two missing boys.

Before long, the faces of missing children were appearing on milk cartons across the US as part of a program developed by the US National Child Safety Council to generate public awareness and track down missing kids.

Prior to the establishment of this program there had been no way of tracking missing children across state lines.

The Milk Carton Kids Program became practically obsolete in the 1990s with the introduction of the Amber Alert System, a child abduction alert system distributed by media channels and via SMS still used in the US today.

But whatever happened to the missing children? Those smiling faces on the side of the milk cartons? We found out.

Related: Authorities have found 123 children in a one-day sweep

Related: Man claims he suffocated the ‘milk carton boy’

Related: FBI search for the very first ‘milk carton kid’

ETAN PATZ

Patz was the first child to appear on the side of a milk carton, and his image and story would become one of the most well-known of the “Milk Carton Kids”.

Patz disappeared in Manhattan in 1979 as he walked to the school bus stop alone for the first time.

Although the bus stop was only two blocks from his home, the six-year-old never boarded the bus.

At that time, there was no nationwide system to help locate or track missing children in the US, and his story helped launch the Missing Children’s Movement and the development of new legislation and methods of tracking missing kids.

One of these early methods was the milk carton program, although Patz had already been missing for five years when his face appeared on the first carton.

It didn’t work.

Etan was declared legally dead in 2001.

Sixteen years later in 2017, Pedro Hernandez was convicted of Patz’s kidnap and murder.

It is alleged Hernandez kidnapped Patz en route to the bus stop and murdered him that day. His body has never been found.

The date of Patz’s disappearance was declared National Missing Children’s Day in the US by President Ronald Regan in 1983.

JOHNNY GOSCH

The subject of countless media portrayals, including a 2014 Netflix documentary Who Took Johnny, Johnny Gosch’s case has had many twists and turns over the years.

Gosch went missing on his usual paper run on the morning of September 5, 1982.

His parents realised something was wrong quite early on, after receiving calls from neighbours that their newspapers were late.

However, because there was no ransom note, police would not declare it a kidnapping and waited 72 hours before declaring him missing and beginning an official search.

Despite his delivery wagon being found less than two blocks away from his house, Gosch was never found.

In 1997, 15 years after Johnny’s disappearance, his mother Noreen Gosch claimed Johnny turned up on her doorstep in the presence of an unknown man in the middle of the night.

The young man, who she vehemently claimed was her missing son, opened up his shirt to show a birthmark on his chest Noreen described as “similar” to Johnny’s.

Although speaking with Noreen for an hour, “Johnny” refused to disclose where he was living, telling her he was “still in danger”, and then he simply vanished again.

In 1984, the Johnny Gosch Bill was passed in his home state of Iowa.

The bill required police to investigate missing children’s cases immediately rather than waiting 72 hours, which was the protocol when Gosch disappeared in 1982.

BONNIE LOHMAN

Bonnie Lohman was only three when she was abducted by her own mother and stepfather from the care of her father.

Despite not being the typical case for the milk carton program, her father managed to have her photo included.

At the age of seven, Bonnie was with her stepfather at the grocery store when she discovered her own face on the side of one milk carton.

She recognised the picture of herself but didn’t understand what it meant.

She asked to keep the image from the milk carton and was allowed on the provision she kept it a secret.

Bonnie’s neighbours discovered her identity when the carton was accidentally left with a bag of toys at their house. They notified the authorities and Bonnie was reunited with her father.

Bonnie is one of the few success stories from the milk carton program.

MOLLIE BISH

At the time of Molly Bish’s disappearance in 2000, the milk carton program was falling out of favour and had barely been used in the past decade.

Out of sheer desperation, Molly Bish’s parents used every avenue available to find their 16-year-old daughter, who disappeared while working as a lifeguard in her hometown, Warren.

This included the offer to put her face on the side of a milk carton.

Unfortunately, Molly was not found alive.

Her remains were discovered three years later only 8km from where she was last seen. Despite some potential leads and suspects, no arrests have been made over her murder.

THE LEGACY OF THE MILK CARTON PROGRAM

Although the milk carton program had limited success in locating the missing children, the legacy of the missing children it featured is significant.

With no widespread system to help locate missing children, the milk carton program arguably pioneered the way in creating public awareness about the cases and child abduction in general, particularly the notion of “Stranger Danger”. It led to changes in legislation and tracking, as well as the development of the Amber Alert System still used today.