NEW YORK (AP) – A woman who was accused of killing her 80-year-old mother-in-law to get her money pleaded guilty Friday to first-degree murder. She also admitted plotting to kill two witnesses.

Diana Nadell, 51, of Cutler Bay, Florida, is scheduled to be sentenced in May to 23 years in prison.

The mother-in-law, Peggy Nadell of Valley Cottage, New York, had been a county Democratic committeewoman and was outspoken on environmental and women’s rights issues. Rockland County District Attorney Thomas Zugibe said she was “a caring mother and grandmother and a respectable and benevolent member of the community.”

Nadell’s daughter found her choked, stabbed and beaten to death in her home on January 25, 2014. Prosecutors said her daughter-in-law and a hired accomplice had lured her to the front door with a phone call, then killed her.

The accomplice, Andrea Benson of Washington, DC, pleaded guilty last year to second-degree murder in exchange for a 20-year sentence. Two other women pleaded guilty to hindering prosecution.

Prosecutors said Diana Nadell wanted access to her husband’s share of Peggy Nadell’s multimillion-dollar estate. The husband has not been charged.

The district attorney said that while she was in jail, Diana Nadell approached a fellow inmate and asked her to take part in a scheme to murder two witnesses who were cooperating with the prosecution.

He said Nadell thought the inmate she approached was about to be deported to Jamaica.

Nadell will be sentenced May 12 to 23 years on the murder conviction and up to 15 years — to be served during the longer sentence — for attempted witness tampering, the district attorney said.