BEDFORD, N.Y. - The Kennedy family, so practiced at public mourning, is grieving again after the estranged wife of Robert Kennedy Jr. was found dead at her home in suburban New York.

Mary Richardson Kennedy, 52, an architect who struggled with drug and alcohol charges in recent years, hanged herself.

The Westchester County Medical Examiner's office said Thursday that she died of asphyxiation due to hanging. A person familiar with the investigation into her death says that authorities have concluded that she hung herself. The person was not authorized to release the information, and spoke on condition of anonymity.

Kennedy's body was discovered Wednesday afternoon at the family's property in Bedford.

Her death came after several hard years for the family. Her husband, Robert Kennedy Jr., a prominent environmental lawyer and the son of Sen. Robert F. Kennedy, had filed for a divorce in 2010. The two had married in 1994 and had four children together.

On Thursday morning, people who knew the family, and some strangers, as well, dropped by home to leave flowers at the front door.

"I think every family has its tragedies. But this is too much. You have to feel for them," said Kim O'Connell, 59, of Bedford Hills, as she dropped off a bouquet of Calla lilies. She said she had met Mary and Robert while working at their health club.

"I just thought she was just a lady. I woke up this morning, and I wanted to do something," she said.

The former Mary Richardson married Kennedy in 1994 aboard a boat in the scenic Hudson River Valley. The couple had four children, the youngest born in July 2001. Robert Kennedy Jr. also has two children from a previous marriage.

She was an architect and designer and had overseen the renovation of the couple's home into an environmentally advanced showpiece.

In a statement issued by Robert Kennedy Jr.'s chief of staff, the family said Mary Kennedy "inspired our family with her kindness, her love, her gentle soul and generous spirit.

"Mary was a genius at friendship, a tremendously gifted architect and a pioneer and relentless advocate of green design who enhanced her cutting edge, energy efficient creations with exquisite taste and style," the family said.

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 attorney Kerry 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 when they were teenagers. She had been Kerry Kennedy's maid of honor at her wedding in 1990 to now-Gov. Andrew Cuomo. The couple later divorced.

But recent years had seen darker moments.

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 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 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 the local newspaper, The Journal News, at the time.

Kerry Kennedy, in her letter, said, "When I look at my three daughters, my wish for them is that they are as blessed as I have been to have a companion, a confidante, a friend, like Mary Richardson."

Mary Kennedy 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.

There were indications her troubles started earlier. In 2007, Robert F. Kennedy Jr. drove his wife to a hospital for treatment, but she resisted and ran from the car, according to the Journal News, which cited Mount Kisco police records.

"I remember she was acting kind of out of it, kind of crazy," a witness, Rae Kesten, told The Journal News in 2007. "She was running into the street and flailing her arms around. He was trying to restrain her. I didn't know if they were fighting or not, but I was concerned."

The unexpected death of another person connected to the storied Kennedy clan brought to mind the other sorrows the famous family has suffered.

Shopping in Bedford, Diane Glokler said, "I've always just thought that family is very tragic. They keep having tragic things happening to them. It's heart-wrenching."

Neighbor Leslie Lampert, who owns the Cafe of Love restaurant a short drive from the Kennedy home, said Mary Kennedy was "at all times just a lovely individual."

"She was community oriented," Lampert said. "She was always kind in our presence."

Another neighbor, Kim Fraioli, a trauma therapist who lives a few houses down from the Kennedys, said the family was private.

"We left them alone," Fraioli. "We didn't have any interaction. I think it's a tragedy. It's very sad for their family and the surviving children. My heart goes out to the family."