Anthony Marshall, the son of Brooke Astor who was convicted in 2009 of stealing millions from his mother's estate, died Sunday, according to a paid death notice in The New York Times.

Marshall, a former Marine, CIA operative, ambassador, investment banker and Broadway producer, was 90 years old. He served eight weeks in prison in 2013 at age 89 before being paroled due to his poor health.

"Tony had the tenderest of hearts, a brilliant mind and an outrageous sense of humor," his wife, Charlene, wrote in his death notice. "It was my honor to love and be loved so tenderly by Tony for more than 25 years. Semper Fi my Tonyness."

Marshall's mother, the famed philanthropist Brooke Astor, died in 2007 at age 105 with an estimated $185 million estate.

After her death, Marshall and an Astor family attorney were accused of tricking Astor into changing her will after she turned 100 and was suffering from Alzheimer's disease. Marshall was convicted of numerous counts, including grand larceny, conspiracy and possession of stolen property.

A year before her death, Marshall was required to return $8 million in cash, artwork and jewelry as well as pay $1.3 million in tax penalties and he relinquished control of her estate to Annette de la Renta, according to The New York Times. Marshall was accused of mistreating his mother in her final days, although Marshall denied any mistreatment and a judge ruled in 2006 that those claims were unsubstantiated.

After his last appeal was rejected in 2013, he became the fourth-oldest inmate in New York state prisons at the time. By that time, he had already undergone cardiac bypass surgery, had a mini-stroke during his trial and suffered from Parkinson's disease. He was paroled just eight weeks into the one to three-year sentence, with the parole board citing debilitating health problems.

At his parole hearing, he said he "naturally" had regrets and he said "quite" when asked if he would have done things differently, according to a transcript of the hearing.

The death notice did not mention either of Marshall's sons, one of whom first alerted authorities about the will being changed and Marshall's alleged mistreatement of his mother.