A pensioner who died could have been given more than three times the correct dose of prescription medicine at her care home.
Jean Halfpenny, 89, was a resident at Orchid View care home in Copthorne, near Crawley, when she died in May 2010.
Police have launched an investigation into her death and a number of people have been arrested on suspicion of manslaughter by gross negligence or neglect.
The Argus has learned that the inquiry centres on an allegation that Mrs Halfpenny might have accidentally been given up to three times the recommended dose of Warfarin for more than two weeks.
The drug is used to thin the blood to try to prevent potentially life-threatening clots forming.
Police believe Mrs Halfpenny received the overdoses before she was taken to East Surrey Hospital in Redhill, where she died.
Officers are also investigating whether prescription records at Orchid View were tampered with or destroyed after Mrs Halfpenny’s death.
The care home has since closed and reopened under a new name and new management.
A spokeswoman for Sussex Police said: “The wider investigation continues to be a long and complex investigation and we are unable to go into further details at this time.”
She added the next of kin of all former patients subject to the investigation have been visited by Sussex Police.
See the latest news headlines from The Argus:
- Minister announces he will step down at general election to "make way for younger candidate"
- Dreaming of a white February
- Well known Hove jewellers close after 57 years in business
- Roadworks on one of Sussex's busiest roads to close lanes and see speed limit drop to 40mph
- Snow alert: Six of the best pictures as the white stuff falls in Sussex again