Martha “Sunny” von Bulow, the heiress who spent nearly the last 28 years in a coma as a result of what Rhode Island prosecutors alleged was a second murder attempt by her husband, Claus, died yesterday morning in a nursing home on the Upper East Side of New York City.

The death of Mrs. von Bulow was confirmed by Lucas Dedrick, the director of the Mary Manning Walsh Home, and Maureen Connelly, a spokeswoman for Mrs. von Bulow’s family. Her family gave her age as 76; records introduced at her husband’s trials and a book written about the case indicate that she was 77.

During the many years that she lay in a vegetative state in a private, guarded room at Columbia Presbyterian Hospital and then, for the past decade, in the nursing home, Sunny von Bulow was not on any life support system. She was fed through a tube in her stomach, Connelly said.

Doctors said she showed no signs of brain activity, but her nurses took care to play her favorite music, “mostly classical” and there were always fresh flowers in her room. Her bedside table was adorned with photographs of her children and grandchildren, according to Connelly.

Mrs. von Bulow lapsed into her irreversible coma on Dec. 21, 1980, when she was found cold and unconscious on the floor of her bathroom in her Newport mansion, Clarendon Court, on Bellevue Avenue.

Her husband, Claus von Bulow, a Danish socialite, was later accused of twice trying to murder her with insulin injections, once in December 1979 and again a year later at their Newport home. His main accusers were her children from her first marriage, Annie Laurie “Ala” von Auersperg Kneissl (now Isham) and Alexander von Auersperg. They hired a private investigator to look into the matter and prosecutors then took the case to a grand jury.

At his first trial in Newport in 1982 –– which attracted an international press crops –– jurors convicted von Bulow of two counts of attempted-murder. He was sentenced to serve 30 years in prison. But von Bulow never spent time behind bars. He was released on bail pending the outcome of his appeal, which was granted, and at a retrial in Providence in 1985, he was acquitted.

His stepchildren then filed a $56-million civil suit against him, but that was settled in 1987 when von Bulow agreed to a divorce and to forego any share of his wife’s fortune, which was conservatively estimated to be worth $75 million. As part of the settlement, von Bulow also had to agree not to talk about the case or his former wife. The couple was divorced in 1988, and von Bulow moved to London, as did the daughter he had with Sunny, Cosima von Bulow, who is now married with three children.

The criminal case severed, for a time, the relationship between Cosima and her brother and sister, because she supported her father throughout the criminal proceedings. Connelly said last evening that the siblings have patched up their differences and noted they had issued a “joint statement” concerning their mother’s death. “They are together in mourning their mother, and they have rebuilt their relationship,” she said.

In their statement, the three children said they’d been “blessed to have an extraordinarily loving and caring mother,” someone who was devoted to friends, family and charitable giving. They said Mrs. von Bulow had been “an active supporter” of the Metropolitan Museum of Art, the Metropolitan Opera and the J.P. Morgan Library, all in New York City, and the Preservation Society of Newport.

Connelly said that Mrs. von Bulow’s two older children live in New York City, but no family members were in the city when she died. “Even though it’s been a long time [that she’s been in a coma], it was unexpected,” Connelly said of the death. Nurses, she said, noticed that “suddenly, she didn’t look well and a few minutes later, she passed away.”

Over the years, Ala Isham, Mrs. von Bulow’s eldest child, told those who inquired that there were three reasons why the family chose to keep their mother alive, even after it became clear that there was no hope for a recovery:

Her mother, she said, did not have a living will so the children had no directive from her as to what she would have wanted; she had the financial resources to be kept alive with round-the-clock nursing and the best care money could buy for however long she lived; and they did not want to cause her any pain. If they had chosen to withhold food and hydration, she would have died a slow death. One of her doctors testified that the cost of caring for her for the first year she was in a coma –– 1981 –– was $375,000. The cost of hospitalization and private nursing care has skyrocketed since then.

MARTHA “Sunny” von Bulow was the only child of Pittsburgh utilities magnate George W. Crawford, founder of Columbia Gas and Electric and Lone Star Gas Company, and his wife, Annie Laurie. Crawford died when his daughter was just 4. She was left a trust worth tens of millions of dollars. Sunny’s mother remarried Russell Aitken; they lived in Newport, not far from where Sunny would later buy her mansion. When Annie-Laurie Aitken died in 1984, she left an estate estimated to be worth more than $100 million, which Sunny’s three children have inherited.

Martha Crawford got the nickname “Sunny” because of her disposition. She was gorgeous but painfully shy. Based on testimony presented by the defense at Claus von Bulow’s second trial, she was also an unhappy woman who overused prescription drugs, laxatives, aspirin and alcohol. During her husband’s second trial, the defense argued that a needle found in a black bag in the couple’s mansion did not show traces of insulin, as the prosecution contended, and that Mrs. von Bulow’s comas had been caused by her own self-destructive behavior and chronic health conditions.

But the prosecution argued that Claus von Bulow was the culprit –– that he’d tried to kill his wife by injecting her with insulin so he could inherit her fortune and marry a soap opera actress with whom he was having an affair.

Sunny von Bulow attended the Chapin School in Manhattan and St. Timothy’s School in Maryland and came out at an elaborate debutante party at her family’s summer estate in Greenwich, Conn. She was driven to school by a chauffeur in a Rolls Royce.

After graduating from high school, Sunny went to Europe with her mother. There, she met an Austrian tennis pro, Prince Alfred von Auersperg. They wed in 1957 when she was 25. The couple settled in Munich, Germany, and then moved to Kitzbuhel in Austria. He had a reputation as a playboy. They had two children but divorced in 1965. (In 1983, von Auersperg was in an automobile accident which sent him into an irreversible coma. He died in 1992.)

Sunny married von Bulow a year after her divorce, and he quit his job as an aide to oilman J. Paul Getty. They moved into a 14-room apartment on Fifth Avenue overlooking Central Park that was decorated with museum-quality antiques.

Mrs. von Bulow then bought Clarendon Court, a 23-room mansion located on 10 acres of waterfront property. The house had been the setting for the 1956 musical High Society starring Grace Kelly, Bing Crosby and Frank Sinatra. The property was sold in 1988 for $4.2 million. That same year, an auction of von Bulow furniture, paintings, porcelains and silver brought more than $11.5 million, The New York Times reported. The Associated Press said the Fifth Avenue apartment sold for $6.25 million.

She is survived by her three children and nine grandchildren. A private memorial service for family and friends is planned for sometime soon in New York City. Burial will be private.

tbreton@projo.com