Doctors in Russia accidentally infected a 16-month-old girl with HIV during a blood transfusion, investigators said Monday, opening a criminal probe into the case.

The toddler was given blood from an HIV-infected donor at the Number 5 children’s hospital in Saint Petersburg, the city’s Investigative Committee said in a statement.

It opened a criminal investigation into “providing dangerous services to children”, an offence carrying a maximum sentence of six years in prison.

The child underwent a transfusion after an operation for life-threatening peritonitis which she developed after doctors took a week to realise that she had swallowed six magnets from a toy.

The girl, named in media as Daniella, will now face lengthy anti-retroviral treatment after contracting the virus which causes AIDS, while still needing a further operation.