A criminal investigation has begun into the death of a woman at scandal-hit Stafford Hospital, the Health and Safety Executive (HSE) has said.
Gillian Astbury died after slipping into a diabetic coma at the hospital in 2007.
An inquest into her death found that the failure to administer insulin to the 66-year-old amounted to a gross failure to provide basic care.
An HSE spokesman said: "Following legal advice, HSE deferred a decision to pursue the investigation into Gillian Astbury's death until the conclusion of the public inquiry, chaired by Robert Francis QC, into Mid Staffordshire NHS Foundation Trust.
"We can now confirm that our inspectors have today formally started an investigation. Our focus will be on establishing whether there is evidence of the employer (the Trust) or individuals failing to comply with their responsibilities under the Health and Safety at Work Act."
The report by Mr Francis highlighted "appalling and unnecessary suffering of hundreds of people" between 2005 and 2009. As many as 1,200 patients may have died needlessly after they were "routinely neglected" at the hospital. Many were left lying in their own urine and excrement for days, forced to drink water from vases or given the wrong medication.
Mrs Astbury, from Hednesford, Staffordshire, died in the early hours of April 11 2007 while being treated for fractures to her arm and pelvis. Jurors at the September 2010 inquest found that a contributory factor in her death was a systemic failure to provide adequate nursing facilities and low staffing levels.
Returning a narrative verdict after the two-day hearing, the 10-member jury said: "We are satisfied that there were serious shortcomings in systems and in implementation, monitoring and management of the systems in place. Nursing facilities were poor, staff levels were too low, training was poor, and record-keeping and communications systems were poor and inadequately managed."
In a statement issued by the Mid Staffordshire NHS Foundation Trust, its director of quality and patient experience, Julie Hendry, said: "I would like to offer our sincere condolences to the family of Gillian Astbury for their sad loss and apologise for the appalling care Ms Astbury received at our hospital in April 2007."
Ms Hendry added: "In 2010 we reviewed Ms Astbury's dreadful care and, as a result, disciplinary action was taken. We will, of course, co-operate fully with the Health and Safety Executive's investigation."