A criminal investigation has been launched into the deaths of four people at Glasgow's flagship hospital.

Officers have been instructed by the Crown Office to act, just days after the mother of one of the children who died said that she believed what happened to her daughter was "murder”.

While the investigation is understood to be at an early stage, it could potentially lead to a fatal accident inquiry or criminal charges.

The deaths being looked at include that of a 73-year-old woman at the hospital campus as well as the deaths of three children.

READ MORE: Parents of children given prophylactic antibiotics at QEUH 'falsely told it was for cancer treatment'

One of those is Milly Main, who died in 2017 after contracting an infection found in water while being treated at the Royal Hospital for Children – part of the same campus as the QEUH.

Her mother Kimberly Darroch this week told an inquiry looking into issues with the construction of the Glasgow hospital campus and the Royal Hospital for Children and Young People in Edinburgh that she believes “what happened to my daughter is murder”.

Ms Darroch told the Scottish Hospitals Inquiry: “My view is that the hospital should be closed. I don’t think it’s safe.”

She added: “I feel like the health board need to be punished for all of this.”

A COPFS spokesman said: “The Procurator Fiscal has received reports in connection with the deaths of three children and a 73-year-old woman at the Queen Elizabeth University Hospital campus, Glasgow.

READ MORE: Child’s death linked to infection at hospital was ‘murder’, mother tells inquiry

“The investigation into the deaths is ongoing and the families will continue to be kept updated in relation to any significant developments.”

The spokesman added: “The Crown Office and Procurator Fiscal Service is committed to supporting the work of the Scottish Hospitals Inquiry and contributing positively and constructively to that work.”

Scottish Labour leader Anas Sarwar said on Twitter: "This is a very welcome and overdue development.

"I have always said that had this occurred in the private sector, there would be a criminal investigation.

"I hope this investigation finds the truth and gets the families the answers & justice they deserve."