Chapel Hill, N.C. — A registered nurse was indicted Monday on a charge of second-degree murder in the February death of an Alzheimer's patient at a Chapel Hill nursing home, authorities said.

Angela Almore, 44, of 724 Berwick Valley Lane in Cary, also was charged with six counts of felony patient abuse. She was taken to Duke University Hospital in Durham following her arrest when she complained of chest pains.

Almore was booked into the Orange County jail Monday night. She was being held under a $500,000 bond. She is due in court on Tuesday morning.

Almore’s neighbor told WRAL News he saw investigators searching through her car on Monday.

Nine of the approximately 25 patients in the Alzheimer's unit at Britthaven of Chapel Hill tested positive in mid-February for opiates, a class of controlled substances often used for pain management, officials said. Six of them were hospitalized, and 84-year-old Rachel Holliday, died on Feb. 16.

An autopsy wasn't performed on Holliday, but a medical examiner who reviewed her records determined that she died because of pneumonia-related asphyxiation. The report lists "morphine toxicity" as a contributing factor to her death, noting that tests done at UNC Hospitals before her death determined she had a morphine level of more than 50,000 nanograms per milliliter of urine.

Drug testing done in the military and many workplaces considers a morphine level of 2,000 nanograms per milliliter as a positive test result.

Officials have said Holliday and some of the other Alzheimer's patients who tested positive weren't supposed to be receiving any pain medication at Britthaven.

The Medicaid Investigations Unit of the state Attorney General's Office pursued the criminal case against Almore as part of its investigation into possible wrongdoing at Britthaven, at 1716 Legion Road.

Britthaven officials declined to comment on the arrest.

Jim Jones, a spokesman for the state Department of Health and Human Services, said Monday that the state Nursing Home Licensure Section would  proceed with its own investigation of any procedural violations now that the criminal probe is finished.

The agency sent a team of inspectors to Britthaven two days after Holliday's death to gather information about drugs administered to Alzheimer's patients there.

Britthaven tested all staff members of the Alzheimer's unit for drugs and placed them on paid leave. The tests came back negative, but a spokesman for the Kinston-based chain of nursing homes said staffing for the Alzheimer's unit remains under review and none of those on duty at the time of hospitalizations have returned to work.

Britthaven of Chapel Hill now monitors the Alzheimer's unit around the clock, and officials have replaced some medication and eliminated some dietary supplements for patients.