Mary R. Kennedy, the estranged wife of Robert F. Kennedy Jr., was found dead on Wednesday at the family’s home in Bedford, N.Y. She was 52.

Ms. Kennedy’s death was confirmed in a statement from her family, who did not comment on the circumstances. Following an autopsy, the Westchester County Medical Examiner said Thursday that she died from asphyxiation by hanging. A person with knowledge of the matter said that Ms. Kennedy’s body had been discovered hanging in a barn behind the house and that she had left a note.

Born Mary Richardson, Ms. Kennedy joined one of America’s foremost political families in 1994, in a marriage ceremony aboard a boat on the Hudson River, near Stony Point, N.Y. At the time, she was an architectural designer at Parish-Hadley Associates in New York.

The couple had four children together; Mr. Kennedy had two from a previous marriage.

Although news outlets have reported that Mary Kennedy and her husband had become estranged and that he filed for divorce in 2010, her lawyer, Kerry A. Lawrence, said on Wednesday that they were not divorced. In 2010, Ms. Kennedy was arrested twice — once on a charge of driving while intoxicated, and later on a charge of driving under the influence of prescription medication.