I clearly remember hearing about the shocking murder — a frightening mystery that colored every day and night in Orinda until an arrest was made. In the meantime, and along with the rest of the town, I watched this whole tale unfold sadly and slowly during the course of several months.
I’d known both girls in a “recognize them and know their names” kind of way — not as friends — but they always seemed just like nice, normal kids. I had known Kirsten since first grade, and had one class with Bernadette at the time of her arrest.
In addition to presenting the story as it was published in November of 1985, I have also added some photos from my own collection, including one from a trip she and I both took to Washington DC with a school group, as well as other pictures from our ’85 class yearbook.
You’ll notice that there are no pictures of Kirsten as a cheerleader. Despite how she’s best known, and though she officially had a place on the squad for the upcoming school year, her life was ended before she ever got to cheer for the MHS team.
They seemed like perfect teenage girls living in the perfect town — until a chilling act of jealousy ended a life and tore a community apart.
The cheerleader murder
by Carol Pogash
A popular and pretty cheerleader, Kirsten Costas, was dead, and sheriff’s deputies were searching for the girl who stabbed her.
The day after the murder in June 1984, rumors had already spread at the tennis courts, down oak-shaded lanes and at poolside. Some claimed it was am an act of Satanism or a PCP-induced killing.
No one wanted to believe that the killer came from Orinda, the lush Northern California suburb where Kirsten lived.
The affluent residents of Orinda cite good schools and a crime-free environment as the main reasons they moved to the town.
Orinda, with a population of about 17,500, lies just thirty-three minutes from downtown San Francisco by Bay Area Rapid Transit. Commuting time shrinks to twenty-five minutes in a BMW, the most popular car at Miramonte High School, where students’ scores are consistently among the highest on California’s state achievement tests.
With a median household income of $60,000, the area’s families are not upwardly mobile — living in Orinda certifies that they have already arrived.
About seventeen years ago, Arthur and Berit Costas moved from Oakland to Orinda seeking a beautiful, safe community with good schools. Attractive and hard-working, they fit easily into their new neighborhood.
The Costases raised two children: Kirsten and her younger brother, Peter. Art became an executive with the 3M Corporation, and Berit stayed home, looking after the kids and the house. The family became active members of the Meadow Swim and Tennis Club, just a stone’s throw from their home.
Although the Costases are quiet, their fifteen-year-old daughter was not. “Kirsten was the energy of the house,” says her mother. “She was always listening to music, making phone calls, dancing. She was full of life. We are simple people. She was raring to go, ready to start to live her life when it was snuffed out.”
Everything about her had flair. “She was cute, not beautiful,” says Sue Morrow, a family friend, “an all-American girl. More like a Sports Illustrated swimsuit model than a Playboy type.”
While she lacked the blond good looks of many of her friends, she had beautiful olive skin, and when she pulled her curly hair brown with golden highlights — back from her forehead, her mother thought Kirsten looked like a Vogue model.
Kirsten, who had just finished her sophomore year at Miramonte, had started to change social circles back in junior high, recalls her good friend Diane MacDonald. By the time she reached Miramonte, Kirsten was in the clique that counted — “the loud crowd,” some kids called it. Wherever the group went, they were noticed.
“We used to say Kirsten had everything,” says one classmate. “She was skinny. She sometimes wore tie-dyed socks, what people are wearing now.”
Another recalls, “I remember watching her after she made cheerleader. Everyone wanted to be like her.”
In the spring of 1984, Kirsten had been asked to join the Bob-o-links, or Bobbies, an elite sorority-like organization of thirty to thirty-five of the best looking, most popular girls in school. In addition to joining the Bobbies, Kirsten was a member of the varsity swim team.
But most important to Kirsten was becoming a cheerleader. She practiced constantly at home in the family room and sometimes at Diane MacDonald’s house, in front of the windows at night, to see her reflection.
Cheerleading, her friend Jessica Grant explains, “is taken really seriously.” Before trying out, applicants write essays explaining what they could add to the school. Parents sign an agreement to spend $500 to pay for green and white uniforms and cheerleading camp.
Girls are graded by twenty judges, and are told their fate at an Academy Awards-type ceremony where outgoing cheerleaders pluck names from envelopes, giving the winners kisses and flowers.
Kirsten was one of the winners. She was, says one of the judges, “a perfect cheerleader.”
Kirsten was attending cheerleading camp, living in a dorm at St Mary’s College in nearby Moraga, when Berit Costas received a seemingly uneventful call on Thursday, June 21, 1984.
The caller identified herself as a Bobbie, and told Berit she knew Kirsten was away until the weekend, but asked if she would be able to attend an initiation dinner for new Bobbies that Saturday night.
When Berit said yes, the caller replied that someone would pick Kirsten up by car, and that no one else should know of the plans.
That Saturday evening, Kirsten’s parents and brother left to attend a potluck dinner for Peter’s Little League team. When a car honked outside the house on Orchard Road around eight-thirty, Kirsten left the TV on, walked out to a mustard-colored Pinto and got in.
A little over an hour later, an agitated Kirsten rang the bell at a stranger’s door. Alexander and Mary Jane Arnold, who live in Moraga, had been playing cribbage with neighbors. When they opened the door, they saw Kirsten and, behind her, another girl, who looked about fifteen, “lurking out the path.”
Kirsten, who appeared tense but not terrified, said, “My friend got weird on me.” She asked to call home. When no one there answered the phone, Alexander Arnold offered to drive her back to a neighbor’s house in Orinda. As they drove, Kirsten seemed unconcerned when Arnold saw the mustard-colored Pinto tailing them.
When the car pulled up to Kirsten’s neighbor’s house, Kirsten assured Arnold she would be all right. Then she got out.
In the meantime, the girl driving the Pinto had quickly parked and slid out of her own car. As Kirsten walked away from Arnold’s car, the other girl swooped out from behind a tall hedge and ran forward with her arm raised. Arnold saw a flash from a metal blade about one-and-a-half feet long. Kirsten fell and sprang up again.
Though mortally wounded, she ran to Arthur Hillman’s house across the street for help.