The son of philanthropist Brooke Astor was accused Tuesday of plundering his mother's $198 million estate and conspiring to have the Alzheimer's-stricken socialite sign a new will leaving her fortune to him.

Anthony Marshall, an 83-year-old Broadway producer, was charged in an indictment unsealed Tuesday and pleaded not guilty at an arraignment. His former attorney, Francis X. Morrissey Jr., was indicted on similar allegations.

Astor died in August at age 105.