Brooke Astor's 83-year-old son charged with changing her will

The 83-year-old son of Brooke Astor, the New York socialite and philanthropist who died in August, faces the prospect of spending the rest of his life in prison following charges that he took advantage of his dying mother, who suffered from Alzheimer's disease, to change her will and enrich himself by tens of millions of dollars.

Anthony Marshall, hitherto known as a pillar of New York society with a background as a diplomat and a Tony award-winning Broadway theatre producer, found himself being arraigned in court earlier this week on a flurry of charges including falsifying records, scheming to defraud and grand larceny.

Mr Marshall's lawyer, Francis Morrissey, also faces multiple charges, including the allegation that he forged Brooke Astor's signature on an amended will he drew up in 2002 and fooled two witnesses into thinking that the changes truly reflected her wishes. Ms Astor, who was 105 when she died, left a fortune estimated at just under $198m. Under the terms of the 2002 will which is being contested separately in probate court Mr Marshall would either inherit or gain personal control of all that money. Discontent over Mr Marshall's handling of her mother's affairs has been brewing for years, and led to a New York judge stripping him of his role about a year before she died and appointing Annette de la Renta, the wife of the fashion designer Oscar de la Renta, as her legal guardian instead.

"As her financial adviser and her attorney, he was supposed to always act in her interest, and it was clear that he was not acting in her interest," New York's district attorney Robert Morgenthau told a news conference as he announced the charges against Mr Marshall.

The criminal investigation, intriguingly, stemmed from complaints made by Mr Marshall's own son, Philip Marshall, who felt his father was not respecting Ms Astor's commitment to financing several leading New York institutions including the Metropolitan Musem of Art and the New York Public Library.

Under the terms of the contested 2002 will, some $66m previously earmarked for charities was cut in half, with the balance going directly to Mr Marshall.

The indictment alleges that Mr Marshall spirited artworks out of his mother's home, gave himself a $1m rise for serving as her financial adviser and spent his mother's money on a number of extravagant items including $52,000 in salary for the captain of his 55ft yacht.

In one instance, according to the complaint, Mr Marshall persuaded his mother to sell one of her beloved paintings Up the Avenue From Thirty-Fourth Street, May 1917, by Childe Hassam by falsely telling her that she was running out of money. Instead of auctioning off the painting, the indictment alleges, Mr Marshall sold it through a private gallery for $10m, pocketing $2m for himself.

Mr Marshall has vigorously protested his innocence, saying he was an effective financial manager of his mother's affairs for a quarter of a century. "We're confident that once all the facts are known, Mr Marshall will be exonerated," his criminal lawyer, Kenneth Warner, said in a statement.

The severity of the charges appears to have come as a shock to Ms Astor's nearest and dearest, including Mr Marshall's son, Philip. "I sincerely hope there is a way justice can be achieved without my father going to jail," the younger Marshall told New York's Daily News, which caught up with him on a walk near his home in Massachusetts.

The New York press is speculating that the affair may well end up with an old-fashioned deal, whereby Mr Marshall restores the money to his mother's favourite causes, and the district attorney's office drops its criminal case. Ms Astor gave $200m to New York institutions during her lifetime, living by her celebrated motto: "Money is like manure, it should be spread around."