A woman in her 80s left at home in Surrey without medication, food, or water for nine days after a care agency shut down has died in hospital.
Gloria Foster was admitted to Epsom Hospital nearly two weeks ago after being found at her home in Banstead.
Her home care provider, Carefirst24 in Sutton, south London closed after a raid by the UK Border Agency (UKBA).
Surrey County Council said Surrey Safeguarding Adults Board was investigating "this tragic event".
Carefirst24 provided care to elderly people across Surrey and the London Borough of Sutton on behalf of the two local authorities.
UKBA raided its headquarters in Upper Mulgrave Road, Sutton, on 15 January as part of an investigation into suspected illegal workers and fraud.
Six people were arrested on suspicion of conspiracy to defraud and conspiracy to assist foreign nationals.
Conservative MP for Reigate, Crispin Blunt, said last week that Ms Foster's ordeal had been horrific and said he expected a comprehensive investigation, between all the agencies involved, to be carried out.
A spokeswoman for the county council said on Tuesday: "We are very sad to hear about Mrs Foster's death, and our thoughts are with her family and friends at this difficult time.
"The safety of vulnerable adults is our top priority, which is why this tragic event is already being urgently looked at by the Surrey Safeguarding Adults Board."
Telephones at Carefirst24's offices are not being answered and no reply has been received to inquiries by email.
All those arrested have been bailed until dates in April.