A day after the estranged wife of Robert Kennedy Jr. was found dead in her suburban New York home, a medical examiner has concluded she died of asphyxiation due to hanging.

The Westchester County Medical Examiner's office issued its conclusion Thursday, after conducting an autopsy on 52-year-old Mary Richardson Kennedy's body.

According to a person familiar with the investigation, who spoke on the condition of anonymity, her death has been ruled a suicide, The Associated Press reports.

College friend Victoria Michaelis said she had not seemed suicidal.

"She was definitely suffering, but she was very, very spiritual and a resolute Catholic," Michaelis said. "I'd say she was depressed the last two years since the divorce. But she would put that aside and ask you how you were. I saw her a couple of weeks ago, and she was fine."

While members of her family have not commented on the nature of her death, they requested privacy and released a statement saying Mary was "a genius at friendship, a tremendously gifted architect, and a pioneer."

It also said "Mary inspired our family with her kindness, her love, her gentle soul and generous spirit."

Her siblings in a statement released Thursday said the recent media portrayal of their sister is "wholly inconsistent with the sister we knew and the life she, in fact, lived."

Mary Kennedy, a prominent architect, struggled with drug and alcohol addiction over the past several years and was arrested twice on related offences.

Robert Kennedy Jr., the son of former Sen. Robert F. Kennedy, filed for a divorce in 2010.

The two married in 1994 and had four children now aged between 11 and 18 years old.

"It's a terrible and tragic time for Mary, her family, and, perhaps most importantly, for Bobby and Mary's children, Conor, Finny, Kyra, and Aidan, and for all of us who loved her," said former U.S. Rep. Joseph P. Kennedy II, a brother-in-law.

Ken Sunshine, a publicist working with the Kennedy family, said a wake is planned for Friday at the family's home. A funeral is expected for Saturday morning.