Strangers sexually assaulted and killed my partner shortly after our fourth child was born, leaving us with only memories of him.

When Bobbie Cowan learned that her partner, and the father of her kids, had been tragically murdered, she felt like her world was collapsing around her.

Calum Simpson was a young man of 24 when he was brutally attacked and killed by Dylan Brister and Cameron Allan. These heartless criminals had drugged his drink, then sexually assaulted him as he lay dying.

Bobbie Cowan had recently given birth to the couple’s daughter, Lyla, just 11 days before Calum’s murder. Now, she faces the daunting task of raising their four children on her own.

Now, she has bravely spoken about the anguish she has had to endure since Calum’s senseless murder.

Bobbie, 26, from Fife, says: “The night Calum went out, we’d had a few words and he left on a bad note. It was nothing serious but I’ll always regret that because they were the last words we ever spoke to each other.

“When he didn’t come home, I felt annoyed that he’d left me to look after the children on my own. I could never have imagined what was coming next.

“My world fell apart when the police came to tell me he was dead. When I found out he’d been attacked and raped, I was sickened. He must have suffered so much.

“The children and I miss him terribly. They each have a teddy bear which has Calum’s voice inside, saying: ‘I love you and I will see you soon.’ It breaks my heart.”

Calum and Bobbie got together at a party in 2015, when she was aged 17 and he was 18.

Bobbie says: “I really fell for him he was funny and kind, and so good looking.”

The couple moved in together and their son, Calum, now eight, was born in August 2016, followed by a little girl, Mirren, in March 2018.

Bobbie says: “Calum was a fun dad, forever tickling the kids and making them laugh. I was the sensible one. We were very much in love but we bickered a lot too, because we were only young.

“With two little ones, money was tight and we were so busy. We started to pick at each other and argue. Suddenly, it felt like a lot of pressure, running a home and raising a family. We were still so young.”

The couple split and Bobbie had a baby daughter, Romi, with a new partner. But her relationship did not last, and she and Calum found themselves back together.

Bobbie says: “I never stopped loving Calum. When he met Romi, he treated her as his own, he was lovely with her, which really made me realise what a good man he was.

“He was round every day, helping out, looking after the kids. I felt myself falling in love with him all over again.”

Heartbreaking news

The couple reunited in May 2020, when Romi was eight months old and in November 2021, Bobbie gave birth to a fourth child, Lyla.

She says: “We were both over the moon when she was born. But Lyla was ill with an infection after she was born and was in hospital for nearly a week.

“It was a really stressful time. When I came home, I wasn’t well, I’d had stitches and I was struggling.

“We had four little ones to look after and we had a silly argument about the housework and the kids; it was nothing.

“Calum said he was going to see a friend and I expected he’d be back either late at night or in the morning.

“I was a bit annoyed he’d left me to look after the kids on my own. I feel terrible about that now but I couldn’t have known.”

The next afternoon, the police came to tell Bobbie that Calum was dead.

She says: “I had Lyla in my arms and they took their helmets off and asked me to sit down which made me panic.

“When they said Calum was dead, I just refused to believe them. They said he was at an address I’d never heard of, so I thought they had got it wrong.

“It was only when they described his tattoo that I realised. I was shell-shocked.

“I was allowed to see him through the glass at the morgue. It was heartbreaking. I could hardly even take in that he was gone. He was just 24 years old.

“He had his whole life ahead of him; four children and a partner who adored him.

“Lyla was only 11 days old. I realised she’d never know her daddy. I’d taken a couple of photos of her and Calum, before we left hospital. Now, I realised, they were all we had.

“This was supposed to be a wonderful, precious time, welcoming our new baby into the family. Instead, I was trapped in a horrific nightmare.”

But there was more heartache to come.

Shocking murder

The police told Bobbie that Calum had been murdered by two men he had never met before.

They had secretly drugged his drinks and after he fell unconscious, they raped him and left him to die.

She says: “It didn’t make any sense. Why would one human being do that to another, for absolutely no reason at all?”

In October 2024, the High Court in Dundee was told that Dylan Brister and Cameron Allan secretly slipped drugs into Calum’s drinks, leaving him unconscious, before tying him up with rope and subjecting him to a sexual assault which they recorded on a mobile phone.

Calum, 24, died from intoxication with the Class C drug Etizolam and alcohol following the horrific attack on him at Brister’s home in Fife, Scotland.

He did not know the two men, had no idea of their wicked intentions, and had only been visiting their home with another friend.

The court heard how Allan and Brister had previously been using gay dating apps to try to lure unsuspecting men to meet them so they could carry out their sick fantasies.

After failing to find a victim they preyed on Calum, who they didn’t know, when he ended up at their flat.

During the trial, the pair tried to blame each other for spiking Calum’s drinks with the controlled drug Etizolam, which is commonly found in so-called ‘street valium’, but is up to 10 times stronger than diazepam.

Brister claimed that Allan confessed he had put the tablets into Calum’s drink, but Allan told the court he saw Brister putting drugs in the victim’s drinks.

Brister, who received almost £1200 a month in benefits, had won more than £20,000 gambling and had bought 1000 tablets for £200.

I was allowed to see him through the glass at the morgue. It was heartbreaking. I could hardly even take in that he was gone. He was just 24 years old.

Bobbie Cowan

Calum’s family had to watch in court as graphic footage recovered from Allan’s phone was shown to a jury, along with photographs of Calum’s horrific injuries.

The court was told that after their attack, the pair left Calum unconscious before going to sleep. In the morning they found him cold and rigid.

However, before contacting the emergency services, they first concealed what remained of their drugs in a safe and handed it to a neighbour.

Emergency services were called at 12:03 and confirmed Calum had died.

Brister, 28, and Allan, 21, were found guilty of sexual assault, rape and murder, and sentenced to life in prison with Brister given a minimum term of 23 years while Allan will serve at least 19.

Brister also admitted attacking two police officers.

Sentencing at the High Court in Dundee, judge Lord Harrower told the pair they had caused “terrible devastation” to Calum’s family.

He said: “There are so many milestones in the children’s lives that their father will no longer be able to share for reasons that cannot adequately be explained to them.

“No sentence of this court can alleviate the family’s grief and anguish.”

Bobbie now says: “I hope they rot in jail. No sentence can ever bring my children’s daddy back.

“I want Calum to be remembered for the kind, loving person he was. He was an amazing father and Mirren in particular looks so much like him, she reminds me of him every day.

“It’s a comfort to know that he lives on through his children, yet it breaks my heart that he is no longer with us.”