Anne Castagna, 43, was arrested Friday for the death of 88-year-old Mary Groatman, The Cherry Hill, N.J., Courier-Post reported.
When police showed up to Castagna's Brooklawn home Friday, Castagna swallowed a substance that caused her to become ill. She had to be revived and was taken to a local intensive care unit before being transferred to the county jail.
The Gloucester County Prosecutor's Office said Groatman was found unconscious Sunday at a rehabilitation center in Deptford after a visit by Castagna. The 88-year-old was apparently poisoned with antifreeze.
Authorities said Castagna, who was Groatman's primary caregiver, and Groatman lived together for more than 10 years until recently when Groatman was transferred to the rehab center for treatment of injures related to a slip-and-fall incident.
Groatman died Thursday after her family decided to take her off of life support.
Authorities recovered a computer at Castagna's that contained information on the effects antifreeze has on the human body. Castagna also purchased antifreeze before visiting Groatman, authorities said.
Castagna is being held in Gloucester County Jail in lieu of her $350,000 full-cash bail.
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