Bernadette Protti



Name: Bernadette Protti

Born: 1968

Died: –

Active: 23 June 1984

Location: United States

Method of Disposal: Stabbing

Consequence: Incarceration in a juvenile facility



  • Kirsten Costas (classmate)


Bernadette Protti’s home life was just fine, by all accounts.  She was born into a devout catholic family, the youngest of six children.  Her father Raymond was a retired public works officer, who taught Christianity in his spare time.  Mother Elaine was a homemaker, who read her bible with a stop watch.

But just fine wasn’t good enough for Bernadette.  She had a habit of looking at the people around her and comparing her own life to what she saw from the outside.  And in her eyes what she had, fell far short of what she believed others considered acceptable.

Bernadette was in her second year at Miramonte High School in Orinda, California.  Miramonte was the only high school in the town, and a microcosm of the social world to the kids of Orinda. 

One of the students that appeared to epitomise Bernadette’s definition of success was a girl in her year level called Kirsten Costas.  Bernadette idolised Kirsten because of the apparent ease with which she seemed to traverse the social minefield.  She started following Kirsten’s lead, figuring that if she simply travelled the same road, she would achieve the same result.

As such, Bernadette and Kirsten were often vying for places within the same teams.  They were both accepted into the Bob-O-Links, a volunteer group with a core purpose of fundraising for a local rehabilitation unit.  It also offered initiates a veneer of elitism, so ‘Bobbies’, as they were called, were more likely to be attending parties than bake sales and blind auctions.  However, true to form, Bernadette was not satisfied.  Being a Bobbie was nice as it opened doors normally shut to people like her, but she saw it as merely a stepping stone.  Now that she had her foot in the door, surely all she had to do now was simply put her hand out.

Unfortunately for Bernadette, that isn’t how life works.  Bernadette and Kirsten both tried out for cheerleader; Kirsten was offered a place, Bernadette was not.  Soon after this, Bernadette put her hand up for the Year Book team, but again she was not accepted.  Bernadette watched as Kirsten took all the success Bernadette believed

was rightly hers due to how well she’d followed someone else.

It was on a ski trip that Bernadette became the most keenly aware that she had not been truly accepted despite her inclusion as a Bobbie.  Bernadette’s family did not have the kind of money that Kirsten’s family did, so her ski equipment was mostly second hand or borrowed from family and friends for her to use.  Kirsten had commented on the shabbiness of her equipment, and Bernadette rankled at what she saw as Kirsten passing judgement on her.

Kirsten would likely have had no clue of the effect her words and actions were having on her fellow classmate. But despite how much the comments hurt, they only served to deepen Bernadette’s resolve to make Kirsten like her. Bernadette was sure that once Kristen was her friend, success would follow.

Yes, Bernadette truly believed that.


The Crime:

On 21 June 1984, Bernadette called Kirsten’s house via a pay phone.  She spoke with Berit Costas, Kirsten’s mother, telling her that there was a dinner being held in honour of the newly-initiated Bobbies the following Saturday.  Bernadette did not give her name during this call, only saying that it was to be a secret known only to the Bobbies.  She said she would collect Kirsten from the house at 6 pm.  Berit told the caller that Kirsten was away until the weekend, but that she would ensure that Kirsten was told.

Bernadette had known that Kirsten was away.  Kirsten was on the cheerleading camp that Bernadette herself was supposed to be enjoying at that moment.  Being reminded of this only gave Bernadette more energy to carry out the plan she had just set in motion. 

Two nights later, Bernadette lied to her parents about needing the car for a babysitting job.  The ruse worked and soon she drove up to Kirsten’s house and honked the horn.  Kirsten came running up to the car, clearly expecting to see someone from her usual inner circle.  Despite her obvious disappointment she got into the car, clearly assuming that Bernadette was her chaperone and she would soon be enjoying the company of the people she actually liked.

It wasn’t long into the trip that Kirsten realised that the dinner she’d been told about was not an actual thing.  The fashion-conscious teen had noted Bernadette’s track pants and faded jacket and deduced that the only party Bernadette was prepared for was a night in front of the tv with a bowl of popcorn. Bernadette admitted to her that she had lied about the dinner, but it was so that they could go to a party instead. Again, her attire told Kirsten otherwise. 

By this time, they had reached the town of Moraga. Kirsten told Bernadette to pull in to the parking lot of a church her family regularly attended. According to Bernadette, they sat in the car for 40 minutes, with Kirsten offering her marijuana.  Bernadette said she turned the offer down and so an argument began.

Well, that’s what Bernadette said happened. However, those who knew Bernadette would later state that she would absolutely have accepted marijuana if she thought it would increase her social credibility. It also wasn’t outside the realm of possibility that Kirsten refused to go to a party to which she hadn’t been invited, and Bernadette responded to this by throwing a temper tantrum like a three-year-old in desperation.

Whatever the truth, Kirsten screamed at her that she was being weird. She jumped out of the car and ran to the home of Alexander Arnold. Alexander knew Kirsten, but was surprised to see her on his doorstep this late at night.

Kirsten said she was out with a friend, but that her friend had ‘gotten weird on her’. She asked to use the phone to call her parents.  However there was no answer when she called. Alexander offered to drive her home.

Out in the car, Bernadette watched as Kirsten hopped into the other car. Bernadette followed in her Pinto, dejected and angry that her plan to win over Kirsten one last time had failed. And now everyone was going to find out how weird she really was.  Kirsten would see to that, would revel in this firsthand gossip.

Bernadette saw her carefully cultivated outward persona crumbling with every passing mile as the two cars returned to Orinda city limits.  She watched as the other car parked outside of Kirsten’s house. Bernadette sat in the Pinto, unsure what to do next.

Kirsten made a start towards her house, but seemed to then change her mind and started walking towards where Bernadette was parked. Grabbing a knife from the rear passenger seat (I assume that 18 inch knives were standard issue in 1980s model Ford Pintos) Bernadette made her way towards Kirsten, meeting her on the front lawn of Kirsten’s neighbour’s house.

Kirsten backed up, yelling at Bernadette to go away. In response, Bernadette started stabbing.  The knife caught Kirsten twice in the stomach, then in her hand as Kirsten raised her arm to protect her body.  As Kirsten fell, the knife was driven twice into her back.

When she realised what she had done, Bernadette ran back to the car and drove off.  She was followed closely by Alexander, who’d seen the fight and given chase to try to catch the girl.

Kirsten staggered to the front door of the neighbour’s house and banged on the door. She collapsed on the ground as the door opened. Arthur Hillman cradled her head and yelled for his son to call 911.  He asked who had stabbed her, but Kirsten was unable to speak.

The police and ambulance arrived quickly. Critically injured, Kirsten was transported to hospital. Alexander returned to the scene and was spoken to by police.  He described seeing a ‘chunky’ teenaged girl with ‘stringy blonde hair’ in track pants driving a Ford Pinto.

Bernadette arrived home at around 10pm. She was sure that Kirsten would have told the police what had happened before they even had time to show their badges. She waited for the knock at the door, the ride in the back of a police cruiser, the good cop/bad cop interrogation.  But the hours passed, and nothing.  She and her mother even went for a lovely late evening walk.  It was like the past couple of hours hadn’t even happened.

But those hours had happened and by 11pm, Kirsten was pronounced dead.


The Investigation:

It was a quite a while before Kirsten’s mother Berit could be interviewed.  She told the police officers about the cryptic call made to the home earlier in the week about the Bobbie initiation dinner.  Coupled with the witness account from Alexander Arnold of the killer with the blonde hair and casual attire driving the Pinto, a scenario was beginning to form in the minds of investigators.

The police interviewed all Kirsten’s associates, including all members of the Bob-O-Links. However, there just didn’t seem to be any one girl who stood out as likely to have committed the crime.  Sure Bernadette had fit the description, right down to the Pinto.  But she had told them she’d been babysitting for the Weems family.  And besides that, she’d passed a polygraph. Polygraphs are foolproof, as history will attest. So they never made the phone call to the Weems to confirm. 

The police finished all interviews, ran down all leads, and came up empty. 

A rumour had been circulating since the funeral that the person responsible had attended to ‘mourn’. Bernadette had been there.  Another girl, Nancy Kane, had also attended.  Nancy had once been part of the group Kirsten hung with. But she had fallen out with them and, by the time Kirsten was murdered, Nancy’s animosity towards Kirsten was well known. Nancy had once told Kirsten in front of others that if she didn’t shut up Nancy would kill her.  Nancy started dressing in an alternative style, and was generally unconventional.  Unconventionality was scary to mainstream Orinda, and she was an easy target when the school population needed a scapegoat to blame for such a terrible crime.

And thus, a red herring was born.  Nancy fit the stereotype, and Orinda’s residents were comfortable with this.  So comfortable that when she was interviewed three days after the murder, the police intimated to Nancy that her fellow classmates were pointing to her as the prime suspect.  Nancy didn’t help her situation entirely: she had initially lied to investigators that she was at a movie at the time of the murder instead of with her boyfriend.  Her mother also refused to allow Nancy to take the lie detector test.

Once the rumour took off, Nancy was a virtual pariah, bullied every day for her ‘role’ in Kirsten’s death. By the end of summer break in September 1984, Nancy had transferred to another school.  Her absence at Miramonte High School on the first day back secured her guilt in the eyes of her fellow classmates for quite some time.

With no break in the case by October 1984, authorities were relieved when an FBI profile they’d requested arrived. The profile indicated the perpetrator would have been a female about the same age as Kirsten who was known to her.  The profile also indicated that the individual would likely not be at all remorseful about the killing, which was a surprise to investigators.  The police had assumed that the killer would have crumbled within minutes of interrogation, which suggested that none of them ever parented a teenage girl.

While the police reviewed the case using the profile, Berit and Arthur Costas hired a private investigator.  He began by reviewing the existing evidence, including the interview notes and lie detector tests. Finally, that quick phone call was made to the Weems family. Upon confirming that Bernadette’s alibi was as thin-skinned as her constitution, the private investigator took this information to detectives.

On 9th December 1984, Bernadette was called in for a second interview. The FBI’s profile was read out to her and she was asked whether the profile reminded her of anyone.  “It sounds like me,” she replied.  Bernadette was allowed to leave at that point; she told the FBI agent she wanted time to think. 

At home she tried to speak with her mother about what she had done, but her mother said she was tired.  The next morning Elaine apologised for not being available the night before.  Bernadette handed her mother a letter, but told her to wait half an hour before reading it.  Elaine obliged, pulling out her bible and setting her stop watch for 30 minutes.  Once the timer went off, she put the bible down, opened the letter and read:

“Dear Mom and Dad:

I have been trying to tell you this all day but I love you so much it’s too hard so I’m taking the easy way out. … The FBI man … thinks I did it. And he is right. … I’ve been able to live with it, but I can’t ignore it, it’s too much for me and I can’t be that deceiving. Please still love me. I can’t live unless you love me. I’ve ruined my life and yours and I don’t know what to do and I’m ashamed and scared.


P.S. Please don’t say how could you or why because I don ‘t understand this and I don’t know why”

Soon after, Elaine screeched to a halt in the school parking lot, where she found her daughter waiting.  She called Raymond and all three met at the police station where Bernadette’s confession was recorded.

The news spread rapidly throughout the community that someone had been arrested for Kirsten’s murder.  The next day, every single female student made sure to attend school, regardless of whether they were ill or not.  No one wanted their absence to be noted by others, for fear they would be connected to the crime.


The Trial:

In the lead up to the trial, Bernadette’s defence team attempted to negotiate a plea agreement to second degree murder.  The defence wasn’t disputing that Bernadette had killed Kirsten; they were only arguing that it wasn’t her intention to do so when she had set up the meeting.  Under the circumstances, such a plea would seem like a fairly reasonable thing to do: due to Bernadette’s age at the time of the murder, the sentence handed down would have been the same length regardless of whether the guilty verdict was for first or second degree murder.  If the prosecution accepted this, it would save the county a lot of money that they could then spend on more important things. 

But the plea was rejected.  Bernadette refused to plead to premeditation and the trial to prove whether a 16-year-old teen knew she was going to murder her fellow Bobbie went ahead in March 1985.  There would be no jury, only a judge.

Many witnesses were called, including one of Bernadette’s sisters who explained the presence of the knife as one she used to cut up vegetables in the Pinto on her lunch breaks.  The knife was 18 inches, or 45 centimetres, in length.  Kirsten’s parents argued that no one’s cutting up tomatoes with a knife that’s almost half a metre long. 

During the trial Bernadette’s confession was played in full, in which Bernadette retold her version indicating she had made an attempt to become a closer friend to Kirsten.  It was apparently this action that had led to Kirsten calling Bernadette ‘weird’ and leaving the car.  Speculation also arose during the trial that Bernadette had wanted something more than friendship with Kirsten, and that Kirsten’s spurning of her advances had led to Bernadette decision to silence her rather than suffer the ridicule of entire school population if Kirsten gossiped about her ‘leanings’.  Either way, Bernadette had worked tirelessly to cultivate a social profile that she could be proud of.  Kirsten would surely tell everyone how weird Bernadette was.  In that moment, becoming a social outcast in a place like Miramonte High School was a fate worse than death. 

In the end, the wannabe cheerleader was found guilty of second degree murder, with the judge rejecting the idea that the murder was premeditated.

On 1st April 1985, Bernadette was sentenced.   It seems somewhat appropriate for the sentence to be handed down on April Fools Day: given that Bernadette had tried to plead guilty to the lesser charge, this meant the Contra Costa County had forked out tens of thousands of dollars to find out an answer they already knew.  The judge indicated his concern about this during sentencing, stating that he hoped the trial had served a purpose more useful than as mere ‘entertainment’.



Bernadette was paroled from the California Youth Authority at the ripe old age of 23.  She legally changed her name and moved out of California for a fresh start. 

The Costas family also moved away, relocating to Alaska.

After the guilty verdict, the students of Miramonte High decided Nancy was worthy of their friendship again.  Hooray for Nancy.

This event was immortalised in the movie “Death of a Cheerleader”, a retelling of the crime sympathetic to Bernadette’s point of view that unfortunately comes off as a victim-blaming exercise.  It starred Tori Spelling and Kellie Martin, along with several other actors who will have you saying, “Where have I see that person before?” and typing furiously into Google. 

Incidentally, if you type Bernadette’s name into Wikipedia, you are automatically directed to Kirsten Costas’ page.  Poor Bernadette, after all her hard work she still isn’t popular enough for her own Wikipedia page.


Web References:

New York Times – “16-Year-Old is Held in Killing” – published 17 December 1984
viewed 15 April 2017

Los Angeles Times – “Girl, 16, Convicted in Classmate’s Slaying : Teen-ager Feared Victim ‘Was Going to Tell People I Was Weird’” – published 14 March 1985
viewed 15 April 2017 – “Murder of Kirsten Costas”
viewed 15 April 2017 – “Bernadette Protti
viewed 15 April 2017 – “‘Bernadette Protti, Kirsten Costas: Cheerleader Murder On ID’s ‘1980s The Deadliest Decade,’ Plus The Obsession With Finding Bernadette Protti
viewed 15 April 2017 – “In a Deadly Explosion of Teenage Unhappiness, One Life Is Cut Short, Another Blighted by Murder
viewed 15 April 2017
Horrific True Stories – “A Friend to Die For
viewed 15 April 2017 – “The Real Death of a Cheerleader Story
Part 1:
Part 2:
Part 3:
viewed 15 April 2017

Movies and Documentaries:

Death of a Cheerleader–0qeE

Bernadette Protti documentary

The 1980s: The Deadliest Decade – S01E03 – The Cheerleader Murder


    • Anonymous on February 28, 2018 at 8:02 am
    • Reply

    Sad that she got to go on with her life under a new name.Should have made her keep her name,we all get jealous but murder is never the answer.But never the less she will have to answer to God when her time comes and I’m sure she will be judged rightly.

    • Karin Yates on January 20, 2020 at 6:01 am
    • Reply

    When girls like Costas torment/bully girls like Bernadette, the tormented can just flip. So sad for all. I hope that damn school has learned a lesson. Too bad there were not alternative/charter schools.A testament to not being a privileged little bitch in an affluent high school.

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