Nikki’s cousin was the one who found her. She was lying face up on the kitchen floor, blood matted around her head. The community was in shock. Everyone knew Nikki, and nobody had a bad word to say about her.
A violent murder was unheard of in Letchworth. It just didn’t make sense. There was broken porcelain on the floor and blood everywhere. A neighbor’s video showed a threatening man walking past a home holding an axe.
Police were called to a block of flats on a quiet housing estate. Nikki’s cousin had become worried when Nikki failed to pick up her mom from a hospital appointment. That was unlike her. She went round to Nikki’s flat, knocked, got no answer, then went to get spare keys.
When she let herself in, she found 26-year-old Nicola Collingborn dead on the kitchen floor. The attending officers could see the head injury. They could also see a cut to her wrist. A broken ceramic pot—actually a ceramic chicken used to hold eggs—lay nearby, stained with blood.
Nikki was holding a dustpan and brush. It was a confusing scene. Did Nikki have an accident? Was she attacked?
The golden hour principles kicked in. That’s the time immediately after an offense when evidence is at its ripest—DNA, fingerprints. Crime scene officers went in straight away to examine the scene and take samples for forensic analysis. I was the first journalist on the scene.
It was just after 8 a. m. when we got the call. The mood was eerie.
From the outside, there was no sign of anything harrowing. A police car sat there, but it could have been there for anything. I spoke to a couple of residents. One woman said someone had died in one of the flats.
At first, we thought it might be a suicide, but the way she put it—there was such a mess, so much blood—we thought it couldn’t be. News of Nikki’s violent death spread quickly. Murder here was unusual, and Nikki didn’t fit the profile of a typical victim. She was born and bred in Letchworth.
She loved children and worked in a nursery. She lived alone, was single, and her family said she was looking for the right man to have children of her own. She was the primary carer for her ill mother and often took her to the hospital. People relied on her.
She was a popular person on the estate. Her family refused to believe she’d taken her own life. She loved life too much. She would never have left her mom, who relied on her.
Investigators believed Nikki had been dead at least a day before she was found. The first impression might have been suicide—there was a cut to the wrist consistent with self-harm, but there was a lack of blood from the wrist. That didn’t add up. You have to keep an open mind, but you also have an instinct.
A broken ceramic pot, a dustpan and brush in one hand, a cut wrist, and a clear head injury—it just didn’t look right. It was clear Nikki hadn’t taken her own life. Somebody else was involved. She’d been murdered.
The big question was who did it. With no idea who the perpetrator was or their motive, detectives canvassed the neighborhood. House-to-house inquiries were vital. People might not know they’d seen something significant.
We need information as soon as possible—anything from a description of a vehicle to a description of a person. Was this a random person who just went to flats and did this? The most important thing was the house-to-house inquiries of people who could see the entrance to the flats. Had anyone seen someone suspicious going in?
Nikki’s flat was on the first floor, in a corridor. If no one was in the corridor, the offender could come and go unseen. Police failed to find an eyewitness, so they refocused on CCTV. The offender had gone in on the ground floor and up to Nikki’s flat.
Police needed a CCTV trawl of the entrance and exit. The home surveillance system in the flats had recently been upgraded. New cameras were installed at the entrance and along the first-floor corridor where Nikki lived. Luckily, a static camera overlooked Nikki’s front door.
Letchworth is an hour north of London, known as a garden city—wide streets, gardens, gaps between houses. It’s not the place you’d associate with violent murders. Nikki’s death became national news within an hour. A lone woman in her flat, a lone attacker—that was frightening for a lot of people.
Detectives struggled to find a motive. One hypothesis was a burglary gone wrong. But nothing was taken from Nikki’s flat. If it were a burglary, you’d expect the offender to have taken stuff, even after death.
They might stage the scene to evade capture, but it just didn’t feel like she was the victim of a burglary. Police went through hours of CCTV, knowing Nikki had died the day before. Then, suddenly, it paid off. When they reviewed the footage from the camera overlooking Nikki’s doorway and the entrance, they saw a man wearing a high-visibility jacket.
He looked like a workman. He went straight to her flat. The footage showed him knocking on Nikki’s door. As she opened it, the figure tried to force his way in.
Nikki pushed against the door, trying to keep him out, but he forced his way in. The intruder arrived at 8:30 on the Monday morning and stayed inside for three hours. The front door didn’t open again until then. The intruder was seen leaving with two small bags.
The discovery was a breakthrough. They now had a good image of the person they wanted to speak to. But it could be any tradesperson in a white van. He could have pulled up, gone into the flat, committed the murder, and driven away.
Police had nothing to go on except one CCTV image of an unknown male. They examined Nikki’s phone and found a number of calls with a local locksmith. It was important to identify that locksmith. Detectives also spoke to Nikki’s family, building up a picture of the victim.
The relatives said Nikki had no problems with any men, no ex-boyfriend disputes. Everybody loved her. The locksmith had an alibi—he’d just gone round to change the locks. Police eliminated him.
At this point, they were frustrated. They had a CCTV image but didn’t know who it was. They’d done a CCTV trawl in the locality—shops, businesses, video doorbells—but the only image of the person they wanted was from the flat itself. At first glance, the footage appeared unremarkable.
A bearded man in a high-vis jacket walking into a building, very nonchalant, not in a hurry. He seemed familiar with the building. He went straight to that door. Police put out a description: a man, large build, light-colored hair, goatee, thick-rimmed glasses.
But when I brightened and enhanced the contrast and colors, something became clear. The goatee was a completely different color from the person’s hair. The work vest had never been worked in—it appeared brand new. Was this a disguise?
Was this person trying to hide their true identity? The autopsy was released. The pathologist didn’t reveal a cause of death, but the fractured skull would have rendered Nikki unconscious. She was the victim of an assault, and the ceramic chicken was the most likely weapon.
The report confirmed Nikki died around the same time the man in the high-vis vest was caught on footage. We’ve got an unknown intruder going into Nikki’s flat. She was assaulted with the ceramic chicken, suffered a head injury, and the cut to her wrist was staged to look like suicide. The person from the CCTV left the scene hours later, after clearing up or staging the scene.
So we know the person responsible is the person on CCTV. If this person was in disguise, what else could the video reveal? Using photogrammetry, a forensic analyst can take measurements from the video to get an approximate height. A person’s height can’t be changed.
The footage had a wide-angle lens creating distortion, but I could correct for it. After undistorting, I told the software where the camera was in 3D space. Using a reference measurement in the real world—let’s say 78 inches—the software calculated the suspect’s height at almost 68 inches, or 5’8”. I’d tell police they’re looking for a suspect approximately 5’8”.
The figure in the high-vis jacket was the detectives’ prime suspect. But who was he? I’m looking at the footage, and I’m thinking they’re not walking right. There’s something about the way they’re moving.
The person is trying to move their arms at the wrong time. It’s not natural. That would pique my interest. A gait analysis was carried out.
A person’s walking style can be distinctive, influenced by age, gender, height, and weight. On initial appearances, the person looked like a man—goatee, dressed masculine. But the gait analysis indicated the offender could be a woman. When you realize this person could be a woman, you ask why they would do that.
Is this person known to Nikki? Detectives turned to Nikki’s family. Had she fallen out with a woman? The family then revealed that Nikki was in dispute with her half-sister, Ivonne Kayla.
They shared the same father, but Ivonne was 27 years older than Nikki. She’d gone to live in America and was quite estranged from the family. Ivonne had left the UK when Nikki was only a baby. When Nikki became an adult, she decided to visit her to get to know her better.
At some point, Nikki went to America to join her and live there for a while. But that didn’t work out. They fell out, and Nikki came back home and got herself a flat. Ivonne then returned from America and moved in with Nikki.
Nikki’s family were surprised she let Ivonne stay in her small flat, but that was the kind, considerate person Nikki was. They had a tempestuous relationship, always falling out. Ivonne was jealous of the relationship Nikki had with their shared father. Living together for four months, their relationship broke down.
During a row, Ivonne lifted a laptop above her head and crashed it to the floor. Nikki was concerned—Ivonne was a much bigger woman. They were always arguing. It got to the point where Nikki evicted Ivonne from her flat.
She had to have the locks changed. It had become that toxic. On the day Ivonne moved out, they had another big argument. Ivonne made an allegation of assault against Nikki, resulting in Nikki being arrested.
While Nikki was being questioned at the police station, Ivonne called a locksmith, claiming she’d locked herself out. She showed identification saying she lived there and was let in. She stole some personal items, including dolls left to Nikki by her grandmother—worthless but very important to her. At the police station, officers told Nikki she had no case to answer.
She went back to her flat and discovered she’d been burgled. When she saw the door had been messed with and the dolls were missing, she knew what had happened. Who else would break in and take those dolls? Ivonne’s actions were risky—she could have been caught.
So this felt like a threat, a way to make Nikki feel uncomfortable. Ivonne was trying to send a message: she is vulnerable. Nikki called the police. Ivonne was charged with burglary.
During that time, she contacted Nikki’s mother, Reena, trying to get her to say some items belonged to Ivonne. With that, she faced a second charge—perverting the course of justice. Ivonne tried everything to make the burglary charge go away. She was getting desperate.
She wanted to stop that burglary trial. While the burglary charge was a potential motive, Ivonne didn’t fit the profile. Sister-on-sister murder in the UK is very rare. For sororicide to occur, the circumstances have to be extraordinary—usually in the context of mental illness or extreme domestic conflict.
Although Ivonne was a good suspect, investigators needed to tie her to the crime scene. Police had reviewed the CCTV many times and now knew the person was in disguise. They took the imagery to family members. Immediately, they identified Ivonne Kayla.
The shock the family must have felt when they realized they could see Ivonne on CCTV, and she’d gone to such lengths to hide her identity. She put a lot of effort into disguising herself to gain entry. What we don’t know is what her intentions were once she got through the threshold. There was bad blood, but the family were shocked Ivonne had gone to this extent.
Detectives believed the disguise was designed to mislead Nikki. If she’d recognized Ivonne at the door, there’s little chance she would have opened it. As part of the investigation, detectives discovered correspondence Nikki had with her GP, saying she was living in fear. She was petrified of her half-sister.
She took a photograph of belongings piled up against her door and sent it to relatives, saying, “This is how I have to live now. ”
Now that police knew it was Ivonne in the CCTV, clearly wearing a fake mustache and probably a wig, they went to the local joke shop. Two employees recognized Ivonne as coming in and buying a fake wig and a goatee beard. Ivonne Kayla was taken into custody.
When interviewed under caution, she didn’t know what the police knew. She was shown the CCTV and denied it was her. She described what she saw as a fat, bow-legged man. “I couldn’t see his face.
”
She referred to the person as male, using “he. ” But just after, she used the phrase “they” because “what they’re wearing look like a dude. ” She slipped from “he” to “they. ”
“Is that you?
Because it ain’t me. ”
She maintained her stance, answering questions as though it were a third person. She’d had time to prepare. When asked, “Do you own a fake beard?
” she almost laughed and shut her eyes while thinking. She’d disposed of it, so the truthful answer was now she didn’t own one. “We suspect that person murdered your sister. ”
“Well, it ain’t me.
”
What I see on that interview tape is a cold, calculated killer trying to stick to a story: It wasn’t me. Ivonne totally denied any involvement in Nikki’s death during all her interviews. But the pressure was on. Police wanted to charge her.
She was a flight risk—she’d previously lived in America, and the concern was she’d try to make her way back there if bailed. Police got the forensic results on DNA from the crime scene. There was blood on parts of the ceramic chicken that rendered Nikki unconscious. Nikki’s DNA was on it, as expected, but also there was blood matching Ivonne.
The blood on the pot could be attributed to Ivonne during the attack. Police reconstructed the chicken-shaped pot, but some pieces were missing. Ivonne tried to clear up the smashed pot but didn’t do a good job—only about half the pieces were picked up. It’s surmised they were in the bag Ivonne carried when she left the block of flats.
There was also blood staining in the bathroom, the DNA matching Ivonne, consistent with an effort to wash her hands clean before leaving. Police could now pinpoint Ivonne at the murder scene at the time of death. She was identified on CCTV by a family member, seen entering the flat at a time consistent with the pathology report, and she’d left her DNA on broken fragments of the ceramic chicken. The evidence was strong enough that police were in no doubt: Ivonne hit Nikki on the head with the ceramic pot, killed her, and staged a half-baked attempt to make it look like suicide.
Ivonne was due to appear in court charged with burglary on the day Nikki died. I believe this angered Ivonne because Nikki was going to testify that Ivonne stole from her. If she got a criminal conviction for burglary, she couldn’t go back to America. Everything had come to a head.
She was so angry she couldn’t stop the proceedings, and the person in the way was Nikki. Police also discovered that on her computer, Ivonne had been making plans to flee the UK. She was looking at ways to get to Spain, possibly driving there, then catching a flight back to the United States. Someone so cold as to plan the murder of their half-sister is a danger to the public.
Who else is she going to kill? Ivonne Kayla was charged with the murder of her half-sister Nikki Collingborn. The community was astounded to learn Nikki had been killed by the woman she’d given board and lodging to. Nikki’s body was released so she could be laid to rest.
Her funeral was a big event. Friends and family from Letchworth and all over the country came to pay their respects. Nikki had an important role—she was her mother’s carer. So this made it even harder for the family to accept her loss.
Sadly, the day before Nikki was laid to rest, her mother, Reena, died. Her family said she couldn’t cope with the death of Nikki. Six months after Nikki’s murder, Ivonne Kayla went on trial at Luton Crown Court. The public gallery was packed with Nikki’s family, all watching Ivonne, who sat motionless in the dock.
Ivonne pleaded not guilty—she was not the person who went to the flat that morning, not the person wearing the high-visibility jacket, the beard, and the large spectacles. The video footage placing Ivonne at the scene was crucial. It was a first-floor flat, one way in, one way out. Luckily, there was a static CCTV camera that caught the killer going in and going out.
Ivonne knew that. That’s why she disguised herself. Local reporter JP Asher covered the trial. Asked by her barrister, “Did you murder your half-sister?
” she replied, “No, sir. ” “Did you have any part in her death? ” “No, sir. ” When presented with the locksmith evidence, she said, “At no point did I call her locksmith.
” When asked about the phone call to Reena, trying to get her to lie about who certain items belonged to, she said, “I have never phoned her ever. She wouldn’t know what I sound like. ” Confronted with evidence of going to a fancy dress shop, she replied, “I would have to cut my hair off to put a wig on. ” Finally, asked if she was the intruder on CCTV, she replied, “Since I left, I have never been back there.
Not once, ever. ”
All the way along, Ivonne ran what journalists might call the “shaggy defense. ” It wasn’t me. To people in court, it was laughable that she went into the witness box and denied being the person wearing a wig, big frame glasses, a fake King Charles the First beard, and a high-vis jacket.
There was extensive scientific evidence—DNA analysis of blood staining—and evidence of motive: the background acrimony between the sisters, culminating in Ivonne being charged with burglary. The killing was carried out on the very day the trial for the burglary charge could have commenced. Ivonne’s actions confuse me. On one hand, some elements were pre-planned—she went out of her way to get a disguise.
But the rest seemed sloppy and impulsive: breaking into Nikki’s house to steal trivial objects, wearing a disguise that Nikki would have recognized easily, attacking her sister so violently, then trying to cover it up so sloppily. To me, it speaks to her chaotic personality. What shocked me about the trial was that Ivonne seemed unfazed by the strength of the evidence. She had overestimated her own abilities to avoid the consequences of what she’d done.
After four weeks, the jury reached a verdict: guilty of murder. There was huge relief from Nikki’s family in the public gallery. Ivonne was impassive. Before sentencing, the judge invited Nikki’s family to give impact statements.
They spoke of Nikki being a wonderful person, how she would have been a brilliant mother, and that she’d had her life stolen from her at such a young age when she had so much to live for. It was heartbreaking. Ivonne Kayla was sentenced to life imprisonment with a minimum of 20 years. The judge told her she was a violent, dishonest, and deceitful person—ultimately a selfish and heartless killer.
As Ivonne was led down to the cells, she looked across at the public gallery, muttered something, and scowled at Nikki’s relatives. Did she show remorse during the trial? Certainly not. Over the years, I’ve covered scores of murder cases, and this must go down as one of the most bizarre.
Ivonne was a manipulative person who needed to be in control. She killed Nikki for revenge and concocted her plan in a most bizarre way. If you saw it on a TV drama, you’d think, why would you do that? You’re not going to get away with it.
Central to the case was the security footage. The availability of CCTV cameras has transformed evidence in court. Gone are the days of police solving crimes by informants. Now they’re trawling through reams of surveillance footage.
It was so unnecessary. It’s bad enough if you kill a stranger, but what sort of person do you have to be to kill your own half-sister? Nikki had her whole life ahead of her. She would have been a brilliant mother.
It was so unfair, so undeserving. What I always found most tragic was that she had taken this person into her home. Ultimately, it was Nikki Collingborn’s kindness that led to this. Nikki was only 26 when she was murdered.
She could have gone on and had a family. Her children could be living on the estate now. We will never know. Ivonne’s actions robbed Nikki’s family of a loving daughter.
The impact has been huge on family, friends, and the community as a whole. It’s absolutely devastating.
