Prosecutors have said there is no evidence that a crime has been committed at an orphanage where the bodies of hundreds of children were reportedly buried in a mass grave.

A BBC and Sunday Post investigation found that at least 400 children from Smyllum Park Orphanage in Lanark are thought to be buried in an unmarked grave at the town's St Mary's Cemetery.

The orphanage, run by the Daughters of Charity of St Vincent de Paul, was home to more than 10,000 children between opening in 1864 and closing in 1981.

Research of death records found that most of the children died of natural causes between 1870 and 1930 from common diseases such as tuberculosis, pneumonia and pleurisy.

Scotland's Crown Office and Procurator Fiscal Service (COPFS) and Police Scotland said they "recognise the level of public concern" following the reports but that there is currently no evidence of criminal activity.

Smyllum Park Orphanage is one of the institutions being examined by the Scottish Child Abuse Inquiry with allegations surrounding the mass grave expected to be studied later this year.

Representatives of The Daughters of Charity of St Vincent de Paul gave evidence to the inquiry in June and said they could find no evidence of abuse.

A joint statement from COPFS and Police Scotland said: "COPFS and Police Scotland recognise the level of public concern following media reports about Smyllum Park Home, including reports that children were buried in unmarked graves.

"COPFS and the police are responsible for the investigation of crime and the investigation of sudden, suspicious and unexplained deaths.

"Based on the information currently available, there is no evidence to suggest a crime has been committed, or that any deaths require to be investigated, but that position will be kept under review.

"Any allegations of criminality will be thoroughly and sensitively investigated."

The Daughters of Charity of St Vincent de Paul told the Sunday Post in a statement: '''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.''

Questioned on the matter by the SNP's Clare Haughey at Holyrood, Minister for Childcare and Early Years Mark McDonald said it was of "great public concern" and highlighted bereavement and child abuse support services funded by the Scottish Government.

He outlined the statement from Police Scotland and Crown Office, saying these organisations and the child abuse inquiry were the correct methods to deal with the matter.

He said: "Any action for the Scottish Government could only follow through proper consideration through these channels first."

Mr McDonald said burials in private ground in the time the orphanage was open were covered by a law dating back to 1855.

He said: "In relation to the unmarked graves that were reported at St Mary's, the legislation that would have applied at the time would have been the Burial Ground (Scotland) Act 1855 but this applied to only local authority burial authorities.

"Private burial authorities tended to follow the legislation voluntarily but there was no legal requirement for them to do so, nor to maintain a register of burials."

The new Burial and Cremation (Scotland) Act 2016 extends legislation over recording burials to include private sites but has this section has yet to come into force.