EXCLUSIVE: When YouTuber Stephen McCullagh's coldblooded plot to get away with murdering his pregnant girlfriend, Natalie McNally, was exposed, his fans were left reeling11:12, 03 Jun 2026For his tens of thousands of followers, YouTuber Stephen McCullagh seemed nerdy, gentle, and perhaps a little pedantic - but behind the facade was a calculated killer.‌The week before Christmas in 2022, McCullagh, 36, murdered his pregnant girlfriend, Natalie McNally, 32, in a savage attack at her home. Today, he has been jailed to a minimum of 31 years in prison at Belfast Crown Court.‌The YouTuber, from Northern Ireland, staged a fake gaming livestream to use as an alibi for the 'savage' and 'prolonged' murder. In the six-hour pre-recorded video, he made secret references to Natalie and killing women in the game he was playing.‌To fans, it seemed as though he was live streaming, but in reality he was using the pre-recorded video as cover to kill his partner. When McCullagh's crimes were discovered, it sent ricochets through the online communities he had played a major role in for many years.As a well known Doctor Who and Robot Wars creator, the killer boasted over 40,000 subscribers. The Mirror spoke to one who unknowingly tuned into the faked livestream, as well as other former fans left digsuted by his sick crime.‌'Shock, denial and betrayal'During the fake live stream, McCullagh claimed technical glitches would prevent him from interacting with viewers as they might normally expect. But this didn't raise any alarm bells for fans watching. "Initially, nothing seemed out of the ordinary. I was very familiar with his claim of his equipment in his home being very crappy and not working too well," one viewer told us. "I didn't see anything bizarre about that...[technical difficulties] were not that much of a surprise to me."Learning the truth about the livestream was 'very surprising'. "We're just so shocked that somebody had this idea 'let me create a fake livestream and then use it to cover my tracks and go do this horrible thing,'" the former fan said.‌The double life the killer was living has left viewers reeling. "In the video games and his fictional videos, yes, he would play violent characters. But all his friends would say he was very soft and gentle and that this was very out of character for him." The former follower added, "I just never felt that he was ever violent in real life".Aidan, 23, another former fan, tells the Mirror: "Back when I was younger, I discovered his YouTube not long after it started, because I was a big Doctor Who fan myself, so I watched all his videos and was really engrossed in it. At one point I was watching every single video he released."‌When he discovered that McCullagh had committed murder, he was in utter disbelief. "I just happened to scroll past an article on Facebook and saw his picture and I was like 'I'm sure about the same YouTuber I used to watch' it was kind of weird, it was disbelief and like 'Surely not, surely, that's not the same person," he explains."In his videos, he always seemed really friendly," Aidan says. "People were just shocked that this person, that a lot of people looked up to, this person that people spent a lot of the time watching videos of, and felt like they almost knew, to a certain degree," had committed such a brutal crime. For his fans it was "shock, denial, kind of betrayal as well."The online Doctor Who fandom was pretty "tight-knit community back in the day", Aidan explains. "It wasn't as big of a thing as it is now. It was more of a niche community that watched his videos, I think it was definitely a kind of bonding thing for people who watched them."‌Aidan describes the faked livestream as "diabolical". "He's obviously put a lot of thought into it. He knew he was going to do it and when. It's just a crazy thought process. He thought he'd get away with it."Another former viewer of McCullagh's videos tells us that in their view, the killer never displayed much of a open personality online. But they felt relieved that no one online jumped to his defence before the verdict, no matter how much they enjoyed his content. "I know there are misogynists and weirdos in every sci-fi community," they explain, "but from what I've seen, everyone unanimously agrees this is awful."Web of liesOnline, he was the nerdy, self-described "man-child" who fans met with delight at Comic-Con. His Doctor Who videos - particularly those about Sonic Screwdrivers - were beloved by many, as was his Robot Wars content. But behind closed doors, calculated McCullagh was living a double life.‌Less than two weeks after brutally murdering his partner and their unborn child, McCullagh posted a black and white photograph on his Instagram account about his grief - the same place he advertised the "Violent Night" stream. In the image he faces away from the camera and it was captioned: "2022 was the worst year of my life. You will never know the levels of suffering, loss, and cruelty I was subjected to, I wouldn't wish it on my worst enemy."This year has torn my soul apart, and I don't know how it can ever be fixed. It feels permanent. I'm not ok and I don't think I ever will fully be myself again. Nothing can help me, I've just lost too much. But I'm still here."‌But behind the harmless front he was putting on was a "cold and clinical" killer, and his pattern of violence is alleged to have gone beyond the horrific attack Natalie endured. McCullagh is alleged to have abused the ex-girlfriend he split up with just weeks before meeting Natalie online.The woman - who cannot be named for legal reasons - claimed during his trial that she once tried to jump out of a moving car, to which McCullagh "said I could kill myself on my own time." She further alleged that he beat her, and that after she suffered a still born pregnancy, he secretly recorded her counselling sessions - the police found these recordings on his computer in 2024.The murder trial at Belfast Crown Court saw a cold-blooded and calculated plot exposed over five weeks, with each detail the court heard even more bone-chilling than the last.‌McCullagh posted a fake 'livestream' on the night of December 18, 2022, chillingly dubbed "Violent Night" and it saw him play video games for six hours.Natalie, who he had matched with on a dating app four months previously, even tuned in from her own home - but it was simply a sick cover. McCullagh was in fact travelling to Natalie's home by bus, wearing a disguise, whilst the 'livestream' took place. When he arrived, he would take her life in a "prolonged" and "savage" attack. Natalie was 15 weeks pregnant with their child.‌Digital forensic experts testified that the "Violent Night" stream had in fact been recorded days before. Initially, McCullagh's attempt to create a false alibi worked, and threw the police off his scent.He went to Natalie's home in Lurgan the day after the murder and "found" her body, alerting the authorities to her death. He was the police's first suspect, but they released him after he used his faked stream to argue he could not have been there.A friend of McCullagh's testified at the trial that the killer "went into detail" about the conditions in which he "found Natalie" and that he was "inconsolable" when he told her the news. "He was howling, crying and screaming," Anne McCullough told the court, adding the convicted killer was "screaming - she's gone, she's gone, Natalie's gone".‌Natalie's grieving family welcomed him during their time of mourning, even allowing him time alone with the 32-year-old's body a the wake. At one stage the killer claimed he "forgot" his phone in their house, when he had actually left it inside recording, so he could find out if they had any suspicions about him.He later posed as a journalist in an attempt to gain information from a police probe, according to the Irish Independent: "PSNI sources said they believed he wanted to find out if he was a suspect. McCullagh was employed by the Belfast Telegraph as a part-time assistant audience editor at the time and never worked as a reporter at the newspaper."‌Dr Ruth Tully, a consultant forensic psychologist who has significant experience working with people who have committed murder, says about the psychological profile of someone like McCullagh: "The manner in which McCullagh planned the murder in advance suggests extreme antisocial and callous personality traits."The mention of Natalie during the filming of the 'alibi stream' indicates she was on his mind even then, and he may have been fantasising about killing Natalie while he was playing the violent video game. If I was working with McCullagh I'd want to explore the level of planning and fantasy within his crime, and these extreme behaviours suggest a need for a personality assessment."The making of an audio recording of Natalie's family, in the context of McCullagh also being alleged to have recorded a former partner during her private counselling session and past reports of assaulting a partner, indicates someone who feels a jealous need to be in control, focusing only on their own wants and needs."Article continues belowFor confidential support, call the 24-hour National Domestic Abuse Freephone Helpline on 0808 2000 247 or visit womensaid.co.uk. If you or your family have lost a friend or family member through fatal domestic abuse, AAFDA (Advocacy After Fatal Domestic Abuse) can offer specialist and expert support and advocacy. For more info visit www.aafda.org.uk.