The probe follows a report by the Daily Mirror of allegations that medics may have hacked into the records of Barnaby Webber, Grace O'Malley Kumar and Ian Coates who were stabbed to death by Valdo Calocane.
Dr Manjeet Shehmar, medical director at Nottingham University Hospitals NHS Trust, said: ‘We are currently investigating concerns that members of staff may have inappropriately accessed the medical records of Ian Coates, Grace O'Malley-Kumar and Barnaby Webber.
‘We have informed the families and will continue to keep them updated throughout the investigation.
‘The families of Ian, Grace, and Barnaby have already had to endure much pain and heartache and I'm truly sorry that this will add further to their suffering.
‘Through our investigation, we will find out what happened and will not hesitate to take action as necessary.'
The news follows an investigation into allegations that Ministry of Justice staff had illegally accessed files relating to the victims.
An NHS England investigation found ‘clear failings' in the treatment of Calocane who has paranoid schizophrenia.
Calocane was sentenced to detention in a high security hospital in January 2024.