On June 23, 1984, Kirsten Costas was stabbed to death by her classmate, Bernadette Protti. Before that night, Bernadette (who was desperately trying to fit in with Kirsten and her “popular” friends) was hanging out with her close friend when she found out that there was a party that some older high-school boys were throwing. Since Bernadette’s friend’s sibling was invited, her friend automatically got an invite and decided to bring Bernadette to accompany her. Once Bernadette discovered this, she instantly thought of inviting Kirsten to the party so she rushed to the phone and called the Costas residence. When Mrs. Costas answered the phone, Bernadette told her that she was a “bobbie” (a school sorority that Kirsten was a part of). She also told her that the “bobbies” were throwing Kirsten a surprise dinner to celebrate her becoming a new member of the sorority and that Kirsten should be ready by 8:30 PM. Mrs. Costas didn’t know exactly who was going to pick her daughter up since Bernadette never left her name.
On June 23, a car horn honked outside the Costas residence. Kirsten rushed out to see who was behind this surprise dinner and discovers Bernadette behind the wheel. Kirsten asked her what was going on and finally realized that there was no surprise dinner. Bernadette tells her that she made the whole thing up but that the real surprise was even better. After Kirsten asks her repeatedly what the surprise was, Bernadette tells her that there was a party being thrown by an upperclassman. Accepting this answer, Kirsten gets in the car and they drive off. On the way, they stop in an empty parking lot so Kirsten can smoke some weed. Kirsten notices a butcher knife and asks about is, Bernadette tells her that her sister like to cut fruits and vegetables in the car. Kirsten accepts it and begins to ask more about this party. She learns that Bernadette wasn’t exactly invited and that they were going to walk into a party that they weren’t invited to. Bernadette tried to explain the situation but was cut off by Kirsten who was telling her to just take her home.
Bernadette was starting to become desperate and yelled at her, “No that would spoil everything!” in which Kirsten responds “There was never anything to spoil!” Bernadette’s last attempt to get Kirsten to stay was to plead with her. She asked Kirsten why she had to be so mean, Kirsten rolled her eyes in response. Then she told Kirsten that all she wanted to do was be her friend and how much she admired her and wanted to be like her. Kristen at this point was “weirded out” and told her that she was pathetic and was acting like she was in love with her. When Bernadette tried explaining herself, she was called a weirdo. Kirsten got out of the car and fled to the nearest house and knocked on the door. She was met by Alex and Mary Jane Arnold and asked them if she could use their phone to call for a ride because her friend had “gone weird on her”. Bernadette was in hysterics, she knew that she was going to be the laughing-stock of the school and that she needed to silence Kirsten before that happened.
Kirsten could not reach her parents on the phone so Mr. Arnold offered to drive her home. On the ride to drop her off, he noticed that a car was following them and asked Kirsten is everything was okay with her and her friend and Kirsten replied “Yeah, she’s just a little weird”. They pulled up to her home and Kirsten got out of the car and thanked Mr. Arnold. She made it to the front door but it was locked. She noticed Bernadette was walking towards her fast. Bernadette muttered to Kirsten, “I would have taken you home” and Kirsten replied “Go Away! You’re so weird!” Then Bernadette began to stab her and then ran off after the fifth stab. Mr. Arnold witnessed the incident and thought it was just a fist fight. He attempted to follow Bernadette’s car but was too late, she was long gone. Kirsten’s neighbor heard her screams and noticed her lying on the ground. They called the police and ran out to comfort Kirsten. An ambulance raced her to a nearby hospital where she was pronounced dead. The knife had gone through a major artery.
Investigators were at Miramonte High School the upcoming week. They questioned students and had many take lie detector tests; Bernadette was one of the chosen ones who took the test. The test came back inconclusive which didn’t point to guilt, but didn’t prove her innocence either. Bernadette’s alibi went unverified and Kirsten’s murder went unsolved for six months. Rumors and theories quickly spread throughout school and the students were pointing fingers, but none pointing to Bernadette. Many students harassed a girl who they believed was responsible for Kirsten’s murder. The student was labeled a ‘goth’ and Kirsten used to pick on her, so many assumed she freaked and murdered her in revenge. Bernadette lived her outward appearance as normal as possible, but inside she was overwhelmed with guilt. Six months later, Investigators went over all their evidence; they finally had a person-of-interest. Bernadette Protti.
After attempting to confirm her alibi and rereading her lie detector test, investigators decided to give Bernadette another lie-detector-test which proved, in their mind, her guilt. They interrogated her in an attempt to gain a confession. After speaking with a FBI officer, Bernadette wrote her mother a letter in which she made a full confession. Bernadette claimed to have found the kitchen knife by chance and her older sister Gina testified in court that she used to have that knife in her car to cut her vegetables. Bernadette Protti was sentenced to a maximum of 9-years, but was released 7-years later on parole. She was released from prison in 1992 at the age of 23.