Betty Broderick, who shot and killed her former husband and his new, younger wife in 1989, a double murder that, with its overtones of marital betrayal, obsession and revenge, was grist for headlines, television movies, talk shows, a podcast and at least five books, died on May 8 in San Bernardino County, Calif. She was 78.

Her death, at a hospital to which she had been transferred last month from the California Institution for Women in Corona, in her 37th year of incarceration, was confirmed by the California Department of Corrections and Rehabilitation. No cause was provided.

On Nov. 5, 1989, Ms. Broderick entered the home of her ex-husband, Daniel T. Broderick III, a prominent malpractice lawyer in San Diego, and Linda Kolkena Broderick, a former flight attendant who became his legal assistant and, while he was still married to Ms. Broderick, his lover, and shot them in bed with a .38-caliber pistol.

Ms. Broderick, then about to turn 42, immediately turned herself in to the police, and never denied firing the fatal shots at her former husband, 44, and his second wife, 28. But she denied committing murder, claiming in media interviews and in the courtroom to have been a victim of years of psychological abuse.

Her two trials — the first ending in a hung jury and the second in conviction on two counts of second-degree murder in 1991 — turned on whether the shootings had been premeditated or were a spontaneous outburst after a long period of what Ms. Broderick described as mental torture.

Her rage at being wronged, and her desire for vengeance, became a mirror in which many ex-wives who had also been through hostile divorces caught a glimpse of themselves.

Ms. Broderick spoke to magazines and newspapers before and after her trials, and twice appeared from prison on “The Oprah Winfrey Show,” angrily venting about her husband.

“He went off with the bimbo at 40, driving a red Corvette — haven’t we heard this before?” she told The Los Angeles Times three weeks after the killings.

She claimed that Mr. Broderick, the head of the San Diego County Bar Association, had used his wealth and legal connections to win custody of their four children and to deprive her of a fair financial settlement when they divorced in 1986.

“His was the white-collar way of beating you,” Ms. Broderick told The New York Times between her trials. “If he had hit me with a baseball bat, I could have shown people what he did and made him stop.”

In San Diego, where the couple had once been socially prominent and lived in a five-bedroom home in the affluent La Jolla community, there was plenty of sympathy for her.

“She worked hard to help send her husband through medical school and law school,” a letter-writer to The San Diego Tribune said. “How did he reward her? He traded her in for a younger model.”

In the years leading up to the fatal shootings, Ms. Broderick’s behavior had grown increasingly volatile. When she first suspected her husband of cheating, she burned his clothes in the backyard.

He moved out in 1985. After that, she spray-painted the inside of his new home, rammed her car through his front door and left vulgar messages on his answering machine. He obtained a temporary restraining order and had her held in a county mental hospital for three days.

At her first trial, mental health specialists called by both the prosecution and the defense testified that Ms. Broderick was narcissistic and histrionic. Melvin G. Goldzband, a psychiatrist who testified for the prosecution, refuted her claims of emotional abuse.

“She wanted not to be rejected,” he said, adding that she would have been angry even if her husband had agreed to an extravagant monthly support settlement.

“People extend battles because it’s the only form of the relationship that they have,” Dr. Goldzband said.

Ms. Broderick was sentenced in 1992 to the maximum possible term: 32 years to life in prison. She was twice denied parole.

Elizabeth Anne Bisceglia was born on Nov. 7, 1947, in New York City, one of six children of Frank and Marita (Curtin) Bisceglia. Her father was an owner of a family plastering business founded by his father in 1908.

She grew up in Bronxville, N.Y., and attended the College (now University) of Mount Saint Vincent, a Catholic institution in the Bronx.

She met Dan Broderick, the oldest of nine children from a Pittsburgh family, when he was on the cusp of entering Cornell’s medical school in Manhattan. They married in 1969. After completing medical school, Mr. Broderick decided to get a law degree at Harvard and enter the lucrative new field of medical malpractice law.

The young couple and their two children moved to San Diego, where Mr. Broderick’s career flourished, two more children arrived and the couple was welcomed into elite social circles. They bought a ski condo in Colorado and dug a swimming pool in the backyard.

But even before Mr. Broderick began an affair, Ms. Broderick was unhappy in the role of socialite and mother, and her family’s privilege seemed to bring her little pleasure.

“Mom was always kind of weird,” her daughter Kimberly Broderick Piggins told The Los Angeles Times in 1990. “Mom would get mad at Dad all the time. Once Mom picked up the stereo and threw it at him. And she locked him out constantly. He’d come around to my window and whisper, ‘Kim, let me in.’”

In addition to Ms. Piggins, Ms. Broderick’s survivors include two sons, Daniel and Rhett; another daughter, Kathy Broderick; and seven grandchildren.

Ms. Broderick and the murders have exerted a long hold on pulpy pop culture. A 1992 CBS television movie appeared in two parts, starring Meredith Baxter. The first installment, “A Woman Scorned: The Betty Broderick Story,” for which Ms. Baxter was nominated for an Emmy Award, was followed by “Her Final Fury: Betty Broderick, the Last Chapter.”

The story was adapted as the second season — broadcast in 2020 on the USA Network — of the anthology series “Dirty John,” with Amanda Peet as the jilted Ms. Broderick and Christian Slater as her adulterous husband.

Bella Stumbo, a Los Angeles Times reporter, wrote a book about the case, “Until the Twelfth of Never,” in 1993, a year after “Hell Hath No Fury” by Bryna Taubman was published.

In 2020, The Los Angeles Times produced a podcast series, “It Was Simple: The Betty Broderick Murders,” which included interviews with the defending and prosecuting lawyers and the jury foreman.

The title was ironic; nothing about Ms. Broderick’s story was as simple as it seemed. At her second trial, the prosecution played a tape of her son Danny, then 11, pleading with her to stop tearing the family apart with her destructive behavior.

“You want everything,” he said. “You want all the kids, all the money, to get rid of Linda — and it’s not going to work, Mom. You’ve been mad long enough.”

Ms. Broderick replied, “No, I haven’t.”