Kasabian was described by friends, neighbors, and teachers as intelligent, a good student, but a "starry-eyed romantic". The girl was known as kind and shy but "forced to grow up too soon". She dropped out of high school and fled her home at the age of sixteen due to increasing problems with her stepfather who she claimed treated both Linda and her mother very poorly. She headed west, looking, she said, for God." She fell into a hippie lifestyle, wandering all over the country from commune to commune, experimenting with psychedelic drugs. She married, divorced, married again, and gave birth to a daughter in 1968. When her second marriage, to hippie Robert Kasabian, began to sour, Kasabian and her baby daughter Tanya returned to New Hampshire to live with her mother. Eventually Robert Kasabian contacted Linda to tell her that he missed his young wife. He invited her to meet him in Los Angeles. He wanted her to join him and a friend, Charles "Blackbeard" Melton, on a sailing trip to South America. Kasabian, who has said she was hoping for a reconciliation, returned to Los Angeles to live with Robert in the L.A. hippie hangouts of Topanga Canyon.
Kasabian was then introduced to Charles Manson, a dramatic event for her. She thought that he looked magnificent in his buckskin clothing, that he seemed Christ-like. Manson talked with her about why she had come to the ranch, and after feeling her legs, accepted her. That night, Manson and Kasabian made love in a Spahn Ranch cave. She thought that Manson could "see right through her" and that he was perceptive of her issues with her stepfather and her feelings of being "disposable" to the people in her life and to the world in general, as recorded in her trial testimony;
Q: "What conversation did you have with Mr. Manson while you were making love?"
A: "I don't recall the entire conversation but he told me I had a father hang-up."
Q: "Did this impress you when he said you had a father hang-up?"
A: "Very much so."
A: "Because nobody ever said that to me, and I did have a father hang-up. I hated my stepfather."
Kasabian adopted the attitude towards Manson that the other ranch girls held: "We always wanted to do anything and everything for him."
Kasabian began joining Family members on their "creepy crawls," quietly sneaking into random homes in Los Angeles to steal money while the occupants slept. These and other criminal activities were the means by which the Family supported itself, and Kasabian was willing to participate. "Everything belongs to everyone," Manson would reiterate during his many philosophical campfire "raps", lectures rendered more powerful by the ingestion of psychedelic drugs. Once group member Mary Brunner was jailed for using a stolen credit card, Linda became the only member of the group to possess a valid driver's license. This, in addition to the fact that in a short period of time she threw herself into life at the ranch and did everything that was asked of her, is thought to be the most likely reason that Linda, a newcomer, was called upon for an important mission.
On August 8, 1969, Manson announced, "now is the time for Helter Skelter", a term taken from a Beatles song that Manson believed (or convinced his associates that he believed) meant a revolution prophesied in the Book of Revelation.(The term actually is british and refers to a spiral slide, popular at fairs and carnivals.) This sense of impending chaos, along with the desire to strike back at the society that had jailed several Family members and possibly create copy-cat crimes that would exonerate Family associate Bobby Beausoleil (arrested in connection with the murder of Gary Hinman), seemed to propel the events of the next two nights. Kasabian was directed by Manson to gather a knife, a change of clothing and her driver's license, then to accompany three other members of the Manson Family (Charles "Tex" Watson, Susan Atkins and Patricia Krenwinkel) to the residence of film director Roman Polanski and his wife Sharon Tate. There, Kasabian witnessed Watson shoot and kill Steven Parent, a teenager who had come to visit the caretaker. Watson then ordered Linda to remain outside the residence, and she stood by the car as Watson, Atkins, and Krenwinkel entered the house and killed Abigail Folger, Wojciech Frykowski, Jay Sebring, and the pregnant Sharon Tate.
Kasabian testified that at one point she heard the "horrible screams" of the victims and left the car. "I started to run toward the house, I wanted them to stop. I knew what they had done to that man [Parent], that they were killing these people. I wanted them to stop. Approaching the house from the driveway, Kasabian was met by Frykowski, who was running out the front door. Kasabian said in her testimony, "There was a man just coming out of the door and he had blood all over his face and he was standing by a post, and we looked into each other's eyes for a minute, and I said, 'Oh, God, I am so sorry. Please make it stop.' But then he just fell to the ground into the bushes." Then Watson repeatedly stabbed Frykowski and hit him in the head. Kasabian tried to stop the murderers by claiming that she heard "people coming" onto the Tate property, but the killers had insisted that it was "too late". According to Watson and Atkins, Kasabian stood rooted to the front lawn, watching with a horrified expression as she observed her companions commit murder. Kasabian testified that, while in a state of shock, she ran toward the car, started it up, and considered driving away to get help, but then became concerned for her daughter back at the Spahn Ranch.
The next night, Manson once again ordered the quartet to gather a change of clothing and get into the car, this time joining them to "show them how to do it," because he felt the deed the night before had been performed sloppily. Joined by Leslie Van Houten and Steve Grogan, the group set off into the city, eventually coming to the LaBianca residence in the Los Feliz area. Kasabian witnessed Manson and Watson walk towards the house and return to the car a few minutes later, whereupon Manson reported that the occupants of the house were tied up. Manson instructed Watson, Krenwinkel, and Van Houten to enter the house. At this point, Manson, Kasabian, Susan Atkins and Grogan drove off. Inside the residence, Watson, Krenwinkel, and Van Houten murdered Leno and Rosemary LaBianca. When asked why she went out with the group again, knowing this time that murder would occur, Kasabian responded that when Manson asked her she was "afraid to say 'no'."
Later the same night, in the Venice Beach area of Los Angeles, Manson asked Kasabian to participate in the murder of an acquaintance, a Lebanese actor named Saladin Nader. Kasabian had met the actor a few days earlier with fellow Family member Sandra Good. Atkins and Grogan waited a few feet away, knife and gun in hand, prepared to kill as per Manson's instructions. Linda purposely knocked on the wrong apartment door in order to avoid causing any harm to Nader. When the occupant answered, Kasabian apologized and excused herself, thus preventing the crime. Two days after the LaBianca murders, she fled from the Manson Family and eventually returned to her mother's home in New Hampshire.
Originally, an offer of reduced sentence (life imprisonment instead of the death penalty) had been given to Susan Atkins for her testimony, since she was the first defendant in custody and had agreed to tell her story at a grand jury proceeding, but Atkins relinquished this chance when she resumed her allegiance to Manson and repudiated any incriminating statements. Subsequently, the prosecution turned to Kasabian, who had voluntarily turned herself in to New Hampshire authorities and traveled back to California. She was offered immunity in exchange for turning state's evidence. There were reports that Kasabian wanted to tell her story to the prosecution with or without any kind of deal, to "get it out of my head," as prosecutor Vincent Bugliosi described it, but that her attorney, Gary Fleischman, insisted that she remain silent until the district attorney produced an offer. Kasabian, by then pregnant with her second child, agreed readily to the immunity offer.
This was seen as a somewhat controversial, option for the prosecution for a number of reasons. Though Kasabian had not prevented the crimes or contacted authorities afterwards (hence the controversy), she had not entered either residence and had not physically participated in any of the murders. She had been described as reluctant and extremely upset during the events of both nights, even challenging Manson ("I'm not you, Charlie. I can't kill anyone."), and was the only member of the group to express remorse and sympathy for the victims. When brought back to the Tate residence to help reconstruct the crime there, Kasabian reportedly suffered an emotional breakdown. The prosecution was relieved to withdraw the deal from Atkins, whose behavior and statements seemed especially depraved.
Taking the stand, Linda Kasabian was the star witness and tearfully recounted the murders in vivid detail. She relayed to the jury all that she had seen and heard during her stay with the Family and during the commission of the murders. Her extremely candid, emotional, and unwavering testimony was considered the most dramatic segment of a very long trial, receiving an unprecedented amount of media coverage. During the trial, the unjailed members of the Manson Family led a campaign of intimidation against Kasabian in an effort to prevent her from testifying. The defendants constantly disrupted her testimony with a blizzard of dramatic courtroom theatrics. Manson would run a finger across his throat, glaring at Kasabian as she testified, an act he would repeat during the testimony of other prosecution witnesses. Susan Atkins would also whisper to Linda across the courtroom "You're killing us!" to which Kasabian responded "I am not killing you, you have killed yourselves". Finally, Manson famously interrupted Kasabian's testimony by holding up a Los Angeles Times newspaper to the jury with the headline "Manson Guilty, Nixon Declares" referring to President Richard Nixon's statements to the press about the pre-verdict trial. It had been Manson's hope that the stunt would result in a mistrial, for which the defense argued but lost. Judge Charles H. Older refused to allow the defendants to legally benefit from the antics.) The female defendants were also noted for giggling like schoolgirls during Kasabian's description of the murders, as though the killings were nothing more to them than a game.
For the majority of her 18 days of testimony the defense attorneys tried unsuccessfully to discredit Kasabian by bringing into account her extensive use of LSD and by attempting to perforate her story. Unfortunately for the defense, the petite, 5'1" Kasabian refused to break under intense cross-examination, and her testimony matched all of the physical evidence in addition to being supported by subsequent prosecution witnesses.
During Kasabian's cross-examination, Manson defense lawyer Irving Kanarek attempted to unnerve her by showing her color crime-scene photographs of the Tate murders. Kasabian's strong emotional reaction to the photographs only served to emphasize, in the eyes of the jury, the press, and even the defense attorneys, her humanity and inability to commit such horrific acts, in stark contrast to the defendants. Manson and Krenwinkel defense attorney Paul Fitzgerald would later assert that this tactic of Kanarek's—meant to discredit Linda—was a grave error that from a trial perspective completely backfired and exonerated the state's primary witness even more. Composing herself enough to look up from the color photo of a very dead, pregnant, bloody Sharon Tate, Kasabian immediately shot a look across the courtroom to the defendants. "How could you do that?" she asked her former friends. The female defendants laughed. Manson defense attorney Kanarek asked Kasabian how she could be so certain, considering her LSD use, that she had not participated in the gruesome act. "Because I don't have that kind of thing in me, to do something so animalistic!" was Linda's response.
Although the Tate-LaBianca trial would go on for nine months with testimony from countless witnesses (including several other former Family members), it is believed that Linda Kasabian's powerful testimony, more than anything else, led to the conviction of Manson, Watson, Atkins, Krenwinkel and Van Houten.
Though not of the same ilk as her former associates, she is reported to have led a troubled life. She had numerous traffic violations until a car accident left her partially disabled. During an Easter celebration in New Hampshire in 1978, she along with friends interfered with firefighters who were attempting to extinguish a bonfire. Though she had completely disconnected all ties with the Manson group, the Secret Service nevertheless subjected her to considerable monitoring and harassment after her former Manson associate Lynette "Squeaky" Fromme attempted to assassinate President Gerald Ford, and she was the target of scorn from the few remaining but loyal and potentially dangerous Family members. Relocating to the state of Washington, she had legal troubles involving the possession of drugs.
Over the years, Kasabian has refused most media attention, surfacing only once for an interview with the syndicated American television show A Current Affair in 1988.
A popular British rock band, Kasabian, is named after her.