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(CNN) -- A New York medical examiner will begin an autopsy Thursday on Mary Kennedy, the estranged wife of Robert F. Kennedy Jr., who was found dead at her Westchester County home. She was 52.

Her death is the latest for a family that has seen its share of tragedy.

"We know from a history of this family, it's very hard being a Kennedy, either being a blood Kennedy or being married to one," Laurence Leamer, a Kennedy biographer, said on CNN's "Erin Burnett OutFront." "The overwhelming celebrity, the attention, the obligations, the expectations that you're supposed to do something with your life. It's very, very hard."

In 1968, Robert F. Kennedy Sr. was assassinated in California while making a run for the White House. His death came more than four years after his brother, President John F. Kennedy, also died at the hands of an assassin.

More than three decades later in 1999, John F. Kennedy Jr., his wife, Carolyn Bessette Kennedy, and his sister-in-law, Lauren Bessette, died when a plane he was piloting crashed in the waters off Martha's Vineyard, Massachusetts. David Kennedy died of a drug overdose and Michael Kennedy was killed in a skiing accident.

Author: It's hard being a Kennedy

Few details of Mary Kennedy's death were immediately available.

The Bedford Police Department confirmed Wednesday that they were investigating a possible unattended death at an address owned by Robert F. Kennedy Jr.

Authorities found a deceased individual inside "an out building" on the property, police said in a statement.

"It is with deep sadness that the family of Robert F. Kennedy, Jr. mourns the loss of Mary Richardson Kennedy, wife and mother of their four beloved children. Mary inspired our family with her kindness, her love, her gentle soul and generous spirit," a statement by the husband's family said.

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

The couple married in a civil ceremony in 1994 when Mary Richardson, a designer, was six months pregnant, according to the Westchester County Journal News. One month prior to the wedding, Robert F. Kennedy Jr. divorced his first wife, Emily Black, the mother of his two oldest children, the newspaper reported.

He filed for divorce from Mary Kennedy two years ago, but the couple was still married at the time of her death, her family attorney, Kerry A. Lawrence, said.

Mary Kennedy was "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," Robert F. Kennedy's family said in a statement.

She advocated finding a cure for food allergies and asthma and was a co-founder of the Food Allergy Initiative, which is the world's largest private source of funding for food allergy research, Robert F. Kennedy Jr.'s family said.

Robert F. Kennedy Jr., a prominent environmental lawyer who is a professor at Pace Law School in White Plains, New York, is the third of 11 children born to Ethel and Sen. Robert F. Kennedy.

Details of the couple's private lives were exposed after Robert F. Kennedy Jr. filed for divorce in Westchester County on May 12, 2010.

The next evening, according to police records, Bedford police responded to a 911 call. When police arrived at the Kennedy residence, they found the couple in an argument over taking their four children to a carnival at St. Patrick's School.

According to a "domestic incident" report filed by the officer on the scene, "Mr. Kennedy stated that his wife was intoxicated and was acting irrational so he took the children to the carnival to remove them from the situation."

No one was injured, the report said.

Two days later, Mary Kennedy was arrested for driving while intoxicated.

At the time, Bedford Police Lt. Jeff Dickans told CNN that a Bedford police officer saw Kennedy's 2004 Volvo swerving onto the curb of Greenwich Road in Bedford and asked her to pull over.

Kennedy had slurred speech, and a blood-alcohol content above 0.08 percent, the legal limit in New York. She was charged with driving while intoxicated.

Lawrence said the case resulted in a reduction to a violation, the criminal charge was dismissed and her driver's license was suspended for 90 days.

A second arrest occurred in August of the same year in the town of Pleasant Valley, in which she was charged with driving while impaired by prescription drugs, Lawrence said. Those charges were dismissed completely in July 2011 because all the drugs were prescribed and taken as her physician advised, the attorney said.

As a designer, Mary Kennedy specialized in green architecture. In a book entitled "Kennedy Green House" and co-authored by Robert F. Kennedy Jr., he describes how he and his wife restored their flooded, black-mold-infested home into an eco-friendly residence.

In the book, her husband wrote that she had worked for the design firm Parish-Hadley and worked on the renovation of the Naval Observatory in Washington, the official residence of the U.S. vice president.

CNN's Michael Martinez and Rob Frehse contributed to this report