OLD BRIDGE, N.J. (CBSNewYork) – A woman has been arrested and accused in the sexual assault and murder of a 73-year-old woman found dead in her home in New Jersey.

Caroline Beckert, 40, of Old Bridge was arrested and charged Thursday with first degree murder, aggravated sexual assault in the first degree, and possession of a weapon for an unlawful purpose in the second degree in the murder of Jo-Ann Cullinan, 73, of Old Bridge.

It’s unclear how these two women knew each other or what possible reason there would be for the alleged crimes by the suspect against a woman 30 years her senior.

Police responded to the Glenwood Apartments and Country Club community after Cullinan’s body was found in her home. The woman was pronounced dead at the scene.

“Been here four years now and never heard or had his happen before,” said neighbor Michael Shantz.

“It’s a quiet neighborhood, something like this is very shocking,” said another neighbor. “Everyone keeps to themselves.”

The neighbor says Cullinan was always friendly, but in recent months her demeanor seemed to change and the neighbor grew concerned.

The results of an autopsy are pending by the Middlesex County Medical Examiner’s Office to determine the exact cause of death.

“She used to wave to me sometimes when she was out here, but in the past year she stopped, so I have a feeling something happened here,” said another neighbor. “She sat out there and she looked like she needed help.”

Cullinan lived at her home with her adult son.

Beckert is currently being held in the Middlesex County Adult Corrections Center pending her initial court appearance scheduled for Friday in New Brunswick Superior Court.

Anyone with information is asked to call the Old Bridge Police Department at (732) 721-5600, or Middlesex County Prosecutor’s Office at (732) 745-3263.