Robert F. Kennedy Jr.'s estranged wife, Mary Richardson Kennedy, who had fought drug and alcohol problems, was found dead in her home Wednesday.

Attorney Kerry Lawrence, who had represented her in a drunken-driving case, said he didn't know the cause of her death at age 52. An autopsy was scheduled for Thursday.

Police confirmed a body was found on Robert F. Kennedy Jr.'s property in Bedford, north of New York City, but wouldn't release the dead person's name.

The former Mary Richardson married Robert Kennedy Jr., a prominent environmental lawyer and the son of Sen. Robert F. Kennedy and nephew of President John F. Kennedy, in 1994. The couple had four children, the youngest born in July 2001.

Mary Kennedy was an architect and designer and had overseen the renovation of the couple's home into an environmentally advanced showpiece. Her family cited her devotion to her children in remembering her.

“We deeply regret the death of our beloved sister Mary, whose radiant and creative spirit will be sorely missed by those who loved her,” the family said in a statement issued by Lawrence. “Our heart goes out to her children who she loved without reservation.”

Mary Richardson had known the Kennedys for years, through her friendship with Robert Kennedy Jr.'s sister, Kerry Kennedy, whom she met at boarding school. She had been Kerry Kennedy's maid of honor at her wedding in 1990.

She had had trouble with drugs and alcohol and had two high-profile arrests around the time her husband filed for divorce in 2010.

Kennedy was first arrested on May 15 of that year on a charge of driving while intoxicated after a police officer reported seeing her drive her car over a curb near the family's Bedford home. Her only passenger was a dog, and police said she had a blood-alcohol level of 0.11 percent; the legal limit is 0.08 percent. Her license was suspended.

At the time of her sentencing, famous family and friends spoke out in support of her.

Her mother-in-law, Ethel Kennedy, wrote in a letter that she “is a caring, nourishing mother who has nursed her four children through lifelong bouts of debilitating allergies,” according to an account in Westchester's The Journal News at the time.

She was charged later that year with driving under the influence of drugs, but that charge was dismissed in July 2011 when a judge said the evidence showed she didn't know the medications she had taken would impair her ability to drive. (AP)