For years, horrific stories have circulated about Scotland’s Smyllum Park Orphanage, which took in 11,600 disadvantaged children between 1864 and 1981. Former residents spoke about vicious beatings, routine humiliations and sexual abuse. Now, an investigation by Ben Robinson and Michael Buchanan of the BBC, in collaboration with Gordon Blackstock of Scotland’s Sunday Post, adds another sordid chapter to Smyllum’s tainted legacy. The journalists’ research suggests that 400 of the orphanage’s young wards were buried in an unmarked mass grave near the notorious institution.

Former Smyllum residents Frank Docherty and Jim Kane first discovered the overgrown grave, located at St. Mary’s Cemetery in the town of Lanark, in 2003. The Daughters of Charity of St. Vincent de Paul, the order of nuns who ran Smyllum, said their records indicated that 120 children had been buried in 158 compartments in St. Mary’s. Docherty and Kane suspected, however, that the remains of many more children lay beneath the soil.

Both men died earlier this year, but the recent journalistic investigation has revealed that their suspicions were likely correct. The BBC and the Sunday Post scoured thousands of death certificates and unearthed 402 records listing Smyllum as the place of death or normal residence. Of those 402 individuals, two were found to have been buried in Glasgow. Burial records were not uncovered for the other 400 children, leading the investigative team to conclude that they had been interred in the unmarked grave.

“It is believed most, without parents or families able to pay for funerals, are buried at St Mary’s,” Blackstock writes in the Sunday Post.

The revelations have drawn comparisons between Smyllum and the Bon Secours Mother and Baby Home in Tuam, Ireland. That institution offered shelter to unwed mothers and their children between 1922 and 1961; earlier this year, excavations suggested that as many as 800 children may have died and been buried in unmarked grave at the home.

Death certificates from Smyllum indicate that, on average, one child died at the orphanage every three months. According to the BBC, a third of those who died were aged five or less.

Most of the children succumbed to illnesses like tuberculosis, flu and scarlet fever. But Andi Lavery, founder of the advocacy group White Flowers Alba, told Samantha Schmidt of the Washington Post that he read through the death certificates, and saw that “many” listed malnutrition and blunt trauma to the head as causes of death.

“Why should they be dying from starvation?” Lavery asked. “Why should they be dying from treatable infections? Why should they be dying from beatings?”

The allegations against Smyllum are currently being investigated by the Scottish Child Abuse Inquiry, which was established in 2015 to look in detail at more than 60 institutions.

In June, Ellen Flynn, head of the British province of the Daughters of Charity of St. Vincent de Paul, denied knowledge of abuse at Smyllum. “We are very apologetic, but in our records we can find no evidence or anything that substantiates the allegations,” she told a member of the inquiry.

The Daughters of Charity of St. Vincent de Paul has not responded to questions from reporters about the mass grave, but the order released a statement saying it is “co-operating fully with [the] inquiry,” according to Blackstock.

“We wish to again make clear that, as Daughters of Charity, our values are totally against any form of abuse and thus, we offer our most sincere and heartfelt apology to anyone who suffered any form of abuse whilst in our care,” the statement added.

Although investigations into the orphanage are still ongoing (the Scottish Child Abuse Inquiry will publish its final report and make policy recommendations by October 2019), revelations about the death certificates are providing closure to some families of former Smyllum residents. Among those believed to have been buried in the mass grave at St. Mary’s Cemetery is Francis McColl, who died in 1961 at the age of 13. McColl’s brother, Eddie, told the BBC that he heard Francis had died after being struck on the head with a golf club. But for decades, he was unable to substantiate those claims.

The records unearthed by the BBC and the Sunday Post suggest that the horrible rumors about Francis may have been true: the boy’s death certificate states that he died of a brain haemorrhage.