Charlene Marshall, who played a central role in a high-profile civil suit and subsequent criminal trial in which her husband, Anthony, was convicted of defrauding his mother, the wealthy socialite Brooke Astor, died on Aug. 6 at her home in Northeast Harbor, Maine. She was 79.

A representative from St. Jude’s Episcopal Church in Seal Harbor, Maine, where her funeral was held, confirmed the death but did not provide a cause.

The Astor case had all the makings of a New York celebrity scandal: an ailing matriarch beloved by the city’s elite for her social and philanthropic largess; an only son who had long lived in his mother’s shadow; a nine-figure inheritance; and a will that had been rewritten more than 45 times.

At issue was whether Mrs. Astor’s son, Anthony Marshall, had conspired with a lawyer, Francis Morrissey Jr., to revise the will to direct more money to himself, along the way forcing his mother, who had dementia and died at 105 in 2007, to slash her expenses to keep her fortune intact.

But the heart of the case was the presence of Mrs. Marshall. She was neither named in the suit nor charged with the crime, but in some ways she was the one on trial.

She and Mr. Marshall, a decorated Marine and a former ambassador to several countries, married after they both left failing marriages in the late 1980s. That was a scandal in itself in the small town of Northeast Harbor, where the Astors had a summer home and where Mrs. Marshall’s former husband was the minister at Mrs. Astor’s church.