A student went to a club with her friends, stepped away for just a few minutes, and vanished without a trace. At first, it seemed like she might have simply left on her own. But when police began retracing her final steps piece by piece, the case took a turn so disturbing that it made headlines far beyond the country. Karen Buckley was born on August 21st, 1991 in Ireland.
She grew up on a farm as the youngest of four children. She loved nature and was passionate about football, playing regularly and supporting her local club and the women’s team. After finishing school, Karen earned a nursing degree. She wanted to help people, so medicine felt like the right path.
After graduating, she moved to Britain and worked as a nurse, but she soon realized she wanted to shift into a different area of healthcare. She became interested in occupational therapy, so she moved to Scotland to complete a master’s degree at the University of Glasgow. She began her studies in January 2015, when she was 24. Karen rented a small flat near the university and quickly became friends with other female students there.
On Saturday, April 11th, 2015, Karen and her friends decided to go to a club and unwind after a week of studying. They chose one of the most popular places in the city and had to wait about 20 minutes just to get inside. The girls were having a good time, and close to 1:00 a. m.
, Karen said she was going to the bathroom. She left her jacket at the table and walked away. She never came back. Her friends thought it was strange, but at first they assumed Karen had gotten tired and gone home, forgetting her jacket.
They picked it up and went home themselves, expecting to see her in the morning since they all lived in the same building. But when her friends woke up, Karen wasn’t in her flat. She hadn’t contacted any of them since the night before. They tried calling her, but she didn’t answer.
She hadn’t been active on social media either, which felt especially strange. Karen lived far from home, so she was constantly online, keeping in touch with family and friends. But not that day. By noon, they called the police.
Officers took the missing person’s report, spoke with Karen’s friends, and went to the last place she’d been seen, the nightclub. Police got footage from every surveillance camera and started going through it. Pretty quickly, they spotted Karen outside the club. She had walked out around 1:00 a.
m. , seemingly deciding to head home after all. But according to the footage that followed, a man approached her, and the two started talking. It looked as though they hadn’t known each other before that moment.
After a few minutes of conversation, Karen walked with him toward the parking lot, and they both got into a car. Investigators identified the car as a Ford Focus, but the quality of the footage wasn’t good enough to make out the license plate or the man’s face. The main task became figuring out who he was. Based on the footage, the man didn’t force Karen to go with him.
She didn’t look threatened. Officers were working with two main possibilities. Either the man had offered to give her a ride home, or she may have decided to go somewhere with him. Either way, by that point, she should have contacted someone.
But she still hadn’t. Detectives turned to the media and released the surveillance images. They were published that same day, and it didn’t take long for police to get a call. A man contacted them and said he had been at the club that night with a group of friends, including 21-year-old Alexander Pacteau.
According to him, he was sure the man in the footage was Alexander. Police started looking into him. They found his address and headed over, hoping Karen might be there with him, and that she was okay. But when officers got to the flat and knocked on the door, no one answered.
They left empty-handed. They contacted Alexander’s landlord. After police explained the situation and said Karen could be in danger, he agreed to give them a spare key. The officers went back to the flat.
Less than an hour had passed since their first visit, but just as they started unlocking the door, Alexander suddenly opened it from the inside. Right at the start of the conversation, he said he had actually been about to contact them about Karen. Even though the officers hadn’t really explained the purpose of their visit yet. He confirmed that Karen had left the club with him.
According to Alexander, he brought her back to his flat. They had sex, and around 4:00 a. m. , Karen left.
As they were speaking with him, Alexander agreed to let the officers inside. Right away, they noticed a strong smell of bleach and other cleaning chemicals. On top of that, there was a toolkit and a roll of tape lying on the bedroom floor. They also noticed something weird.
The mattress was much smaller than the bed frame and clearly didn’t belong there. All of it looked suspicious, as if Alexander had been trying to clean something up or hide it. By the time police were there, almost 2 days had passed since Karen disappeared. Investigators knew that, in theory, he could have had enough time to clean the flat pretty thoroughly if something had happened there.
Still, police didn’t yet have any solid evidence proving that. Even so, they asked Alexander to come down to the station with them and give an official statement. At the same time, officers were working on getting a search warrant for his flat and his car. Before long, they had it.
Forensic teams went in to look for evidence. Meanwhile, police received another call. A local resident had found a woman’s handbag and phone near a dumpster by the entrance to a local park. Officers collected the items and found Karen’s ID inside the bag.
They confirmed that the phone belonged to her as well. That park was only a few minutes’ walk from Alexander’s flat. The fact that Karen’s belongings had been dumped was a very bad sign, suggesting she might no longer be alive. Soon, detectives got more evidence, and it only deepened those fears.
Forensic experts found traces of blood in Alexander’s car in two different places: on the passenger seat and in the trunk. Inside his flat, they also found tiny traces of blood in the bedroom and bathroom, which someone had clearly tried to wash away with cleaning products. The blood in Alexander’s car and flat belonged to Karen. Detectives brought him in for questioning again, and this time he changed parts of his story.
He still insisted that everything had happened the way he’d said from the beginning. Karen had come back to his flat, they had sex, and then she left. But now he added a new detail, one that was supposed to explain the new evidence. According to him, Karen had accidentally hit her head on the headboard and started bleeding.
Investigators kept pressing him, asking why he had left that part out during their first conversation. Alexander claimed he had simply panicked when he saw the news about Karen’s disappearance. He thought police might blame him for whatever had happened, and he got scared. So he took the mattress with traces of her blood, along with some of Karen’s clothes that she had supposedly left behind at his flat, drove them out into the woods, and burned everything in a fire.
That explanation sounded extremely hard to believe, but Alexander continued to insist that Karen had been perfectly fine when she left his flat. While detectives were looking for more evidence, police were also going through surveillance footage. They were trying to reconstruct Alexander’s route on the night Karen disappeared, and they managed to spot his car on multiple recordings. Once they pieced everything together, they got the following timeline.
He drove Karen in the direction of her home, but stopped shortly before reaching it. He parked on a quiet street that ran through a park. A street with almost no traffic, especially at night. Alexander’s car stayed there for 12 minutes and 46 seconds.
Then, he drove back toward his own flat. After that, he stopped near the park where Karen’s belongings would later be found. Police didn’t have footage showing exactly what he did there, but they were able to establish that Alexander spent 26 minutes in the park. After that, his car was seen near his home.
Everything suggested that Alexander may have killed Karen right there in the car, while it was parked on that quiet road. Detectives decided to arrest him. When they took him into custody, they found something else in his pocket. A receipt with some very interesting items on it.
According to the receipt, on the morning after Karen disappeared at 9:42 a. m. , he had bought 6 liters of caustic soda, a protective mask, and gloves. Police checked other stores in the area and found surveillance footage showing Alexander buying even more caustic soda, along with drain cleaner, a large plastic barrel, and two padlocks.
Officers spoke with employees at those stores, and one of them said Alexander had actually asked him for advice. He wanted to know the most effective way to clean blood off a mattress. When detectives examined his phone, they found that before buying the chemicals, he had searched online for information about the properties of caustic soda. All of that evidence suggested Alexander had not only killed Karen, but also tried to destroy her body using chemicals.
But there was one problem with that plan. Caustic soda, used in those conditions, would not be able to dissolve a human body. Police knew he still had to have hidden her remains somewhere. By then, the media had learned the suspect’s identity, and the case was being covered heavily.
Just a few hours after Alexander’s arrest, police got a call from someone who knew him personally. After hearing that investigators were looking for Karen’s body, this person decided to share some very useful information. According to him, Alexander had once rented something like a shed on a rural farm, where he kept some of his belongings. Police immediately went to that farm.
The owner told them Alexander had actually come by just a few days earlier and rented the shed again. Officers noted a new padlock on the door, the same model Alexander had bought, and forced it open. Inside, they found a large plastic barrel. And detectives already knew what they were about to see when they lifted the lid.
Karen’s body was inside, covered in caustic soda mixed with drain cleaner. But as forensic experts had expected, the chemicals had not dissolved her body. They had only caused some damage on the surface. The medical examiners determined that Karen had been struck in the head more than 10 times with some kind of heavy object.
But the actual cause of death was strangulation. On top of that, there were deep cuts all over her body made after she was already dead. As soon as detectives received the forensic results, they brought Alexander in for questioning again. And this time, he changed his story.
He admitted Karen had died in his flat, but insisted it had been an accident. According to him, while they were having sex, she hit her head on the headboard and it made her furious. She then slapped him in the face, and in a burst of rage, Alexander grabbed a wrench and hit her around 13 times. After realizing what he had done, he said he decided to get rid of the body using chemicals.
But detectives knew that version didn’t line up with the facts, especially because it didn’t explain the strangulation. Still, at that point, they no longer needed Alexander’s confession. They already had more than enough evidence to take the case to court. Based on everything investigators had gathered, including surveillance footage, location data, and witness statements, police laid out their final version of what happened.
In their view, Alexander approached Karen outside the club when she had decided to take a taxi home. During their conversation, he had offered to give her a ride. His own claim that she had agreed to go to his flat was contradicted by the fact that his car had been driving for quite a while in the opposite direction, toward Karen’s apartment. Then, Alexander pulled over on an empty street and started hitting Karen in the head with a wrench before strangling her.
Once he realized she was dead, he drove back toward his flat, stopping near the park along the way to dump her belongings. After that, he wrapped her body in a bed sheet, carried it into his apartment, left it in the bedroom, and went to sleep. When he woke up at around 8:00 a. m.
, he started thinking about how to get rid of the body. He searched online for information about caustic soda and decided it would be strong enough to dissolve human remains. So he went out and bought everything he thought he needed from several different stores. After that, Alexander filled the bathtub with chemicals and placed Karen’s body inside, first making deep cuts in it so the chemicals would work faster.
But there was one major problem. He didn’t live alone. He had a flatmate who had gone away for a few days, and that flatmate was due back soon. After several hours, Alexander realized the caustic soda wasn’t doing the job.
So he had to change the plan. He bought a barrel, even more chemicals, and padlocks. Then placed Karen’s body inside the barrel and poured the chemicals over her. After loading it into his car, he drove to the farm where he had once rented a shed for storage.
He made arrangements with the owner, put the barrel inside, locked the shed with his own padlock, and then took his mattress, a blanket, and some of Karen’s belongings out of the car. He dumped them on the ground not far from the farm, covered them with fuel, and set them on fire. After that, he stopped at a car wash and paid for a thorough cleaning of the car, inside and out. Then he went back home and started scrubbing the flat before his roommate returned.
Police had a pretty detailed picture of the timeline, but they still didn’t know Alexander’s motive. He hadn’t known Karen before meeting her outside the club, so there didn’t seem to be any personal reason for him to target her. Forensic experts also found no evidence of sexual assault, which essentially ruled that out as the purpose of the attack. But before long, detectives came to a chilling conclusion.
Alexander’s motive may have been nothing more than a desire to kill someone. As they dug into his background, police learned quite a lot. Alexander came from a fairly wealthy family, but when he was a teenager, his father’s business went bankrupt, and Alexander’s life changed dramatically. Instead of attending an elite private school, he had to go to a regular one.
And that was when his behavior started to change for the worse. He became aggressive, kept getting into conflicts, and at 17, he dropped out of school entirely. After that, Alexander came to the attention of police twice. A year before Karen’s murder, he was arrested for counterfeiting banknotes.
He had copied 20-pound notes and tried to use them in a shop, but the cashier noticed and called the police. For that crime, he was given 25 hours of community service. But it was far from the most serious thing in his criminal history. It turned out that when he was 17, Alexander had been arrested for attempted sexual assault.
In 2011, he approached a 24-year-old woman who had just left a club and was trying to get a taxi. He started talking to her and said he was heading in the same direction, suggesting they split the taxi fare and ride together. But shortly after that, Alexander suddenly attacked her, dragged her into a dark alley, and tried to sexually assault her. Fortunately, the victim managed to break free.
Alexander was arrested and facing real prison time. But in court, he insisted that the woman had actually been the one making advances towards him and that he hadn’t been interested. According to him, she became aggressive and then accused him of a crime out of revenge. The jury somehow believed his story, and the charges were dropped, leaving him a free man.
Now, after Karen’s murder, detectives couldn’t ignore the disturbing similarities between the two crimes. But even that wasn’t the end of it. Throughout the investigation, police had been focused on the timeline from the moment Karen left the club. But once they started rewinding the footage further back, they discovered something else.
About half an hour before Alexander approached Karen, he had been caught on camera near the club. At that moment, a woman in a pink dress walked by, and Alexander started following her. He kept his distance and repeatedly hid behind parked cars as if he was trying to sneak up on her without being noticed. But the woman did see him, and what was happening frightened her badly.
Lucky for her, a taxi happened to be driving past, and she quickly jumped inside. So detectives understood that this woman could easily have been Alexander’s victim instead of Karen. She had been saved only because a taxi happened to come down that empty road at the right moment. More than that, all of this suggested Alexander may have been a true predator, someone who didn’t really care who he killed and who most likely would have continued if he hadn’t been caught.
His trial began in August 2015, just a few months after the murder. Even though Alexander had repeatedly changed his story before that, trying to make himself look innocent, he eventually did something unexpected. He admitted to the murder. Most likely, both he and his lawyers understood that with this amount of evidence, he had no real chance of avoiding punishment, and that the only sensible move was to plead guilty in the hopes of getting a shorter sentence.
On top of everything detectives already knew, Alexander said he had thrown the wrench into a canal. At the same time, he showed no real signs of remorse, something noted not only by the judge, but by others involved in the trial as well. He also couldn’t give any clear motive for what he had done. Though by then, everyone understood they were dealing with a potential serial killer who had been stopped after his first victim.
In the end, Alexander was sentenced to life in prison with no chance of parole for at least 23 years. He tried to appeal that decision, but quickly withdrew his request before the appeals court even began reviewing it. As of now, Alexander is still serving his sentence, and there is no guarantee he will be released once those 23 years are up. So in the end, this case was solved extremely quickly despite the killer’s horrifying attempts to cover up what he had done.
It’s worth mentioning that the university where Karen had started studying shortly before her death decided to award her the degree she had been working toward. It was presented to her father. And in 2026, he told journalists that over the past decade, he had forgiven his daughter’s killer and no longer held hatred toward him.
