The woman, Tara O'Leary, was removed on Sept. 11 from a central New Jersey home where she lived along with two other developmentally disabled adults, according to Tom Fitzsimmons, an aide to state Sen. Jennifer Beck.
The state did not release O'Leary's name, but said she died Nov. 10.
"This death is unacceptable on many levels, and we're doing all we can to scrutinize every aspect and prevent tragedies such as this from occurring again," said Jennifer Velez, the state Human Services commissioner.
The case is similar to one in 2003, when four children - all weighing less than 45 pounds - were removed from a state-run foster home in Collingswood. The boys all survived, but their plight brought deep disgrace to the state Division of Human Services and its Division of Children and Family Services.
Pam Ronan, a spokeswoman for the Department of Human Services, said Tuesday the department began investigating O'Leary's care on Sept. 12 - and the Hunterdon County Prosecutor's Office began a criminal investigation the same day.
Ronan said the woman had a complicated medical history, but that the state could not release many specifics because of state and federal patient privacy laws and because of the investigation.
She said the state is looking into whether the caseworker was making monthly visits to the home.
The state has about 600 licensed community care residences, which operate much like foster homes and serve developmentally disabled adults.
Ronan said the state made public some information about the death and the investigation on Tuesday because officials were aware that three lawmakers, including state Sen. Jennifer Beck, a Republican from Red Bank, had scheduled a news conference with two of O'Leary's cousins and an aunt.
