How a content creator hoped a YouTube alibi would help him avoid justice for murder

Cold-blooded, brutal and outlandish - if the plan Stephen McCullagh set in motion to kill his pregnant partner was the plot of one of his video games, it may have been dismissed as being too far-fetched.

But from the content creator's first appearance in court in early 2023, it was clear authorities believed he had not only murdered Natalie McNally but also carefully constructed an elaborate house of cards to avoid justice.

There were his tears when police arrived at the scene, responding to his 999 call and his claims that another former partner of Natalie's had done it.

His presence with Natalie's family in the days and weeks after her death, and even his attempt to spy on their conversations.

Warning: This article contains very strong language which readers may find offensive

And, of course, there was the alibi – the six-hour YouTube gaming 'live stream' broadcast the night before Natalie was found dead, that turned out to be a pre-recorded ruse.

For more than a month after the murder, McCullagh, 36, believed he had been dismissed as a suspect in Natalie's death.

But, three years after being charged, a five-week trial exposed his lies to a jury.

What happened the night Natalie died?

It's 18 December 2022, about 16:00 GMT, and McCullagh posts to his tens of thousands of subscribers that he'll be hosting a live gaming stream from 18:00 on YouTube.

The stream's title is Violent Night.

When the stream appeared, it showed McCullagh playing Grand Theft Auto: Vice City and Robot Wars video games while drinking, vaping and commenting to the camera.

Unusually, he told viewers that he couldn't interact or respond to comments – as streamers usually do – due to technical problems.

But the stream wasn't live at all.

A digital forensic analyst told his trial that evidence indicated the six-hour gaming stream had been recorded four days earlier.

The analyst also said the pre-recorded file was stopped at 00:05 on 19 December and then deleted.

It was during the broadcast that McCullagh murdered Natalie.

'I need to take her down'

Warning: This article contains very strong language which readers may find offensive

Parts of the stream were played to the jury during his trial, and they contained among other things references to violence, crime and relationships.

In the time it is believed Natalie was attacked, McCullagh plays a Grand Theft Auto mission where it is required to kill a woman.

During this, he sings: "I need to kill this bitch, I need to take her down."

About 10 minutes later, he says: "Abso-fucking not-ally, abso-fucking Natalie." It is his only reference to her by name during the stream.

Minutes later he takes a break, during which a poster for the James Bond film No Time To Die briefly, and incongruously, comes up on the screen.

What McCullagh meant with these references has gone unexplained - he did not take the stand during the trial.

Hours before McCullagh's recorded stream was posted to YouTube, Natalie McNally was in her parents' home watching the World Cup final and enjoying a Sunday dinner.

She and McCullagh exchanged messages just before he posted the stream – he said he was about to "stream the night away" and she said she would try to "sneak a peek at it".

A short time later, Natalie drove back to her own house, arriving at about 19:00.

By this stage, McCullagh is walking about two miles from his home in Lisburn to Dunmurry where he catches a bus to Lurgan 20 miles away.

He is wearing dark clothes, gloves and has the bottom half of his face covered and is carrying a green shopping bag.

Earlier, he had looked up bus and train timetables to and from Lisburn, Dunmurry and Lurgan.

When he arrives, he walks for just more than a mile and a half to Natalie's home at Silverwood Green where he brutally kills her.

Police say the killing happened between 20:50 and 21:30. She is stabbed, strangled and suffers at least five heavy blows to the head.

McCullagh's return journey is extensively captured by CCTV.

Before embarking, he changes his clothes.

Trial prosecutors highlighted images of McCullagh, from his social media, that show him wearing a black hat and wig that bear a resemblance to the man who appears in footage walking back through Lurgan town centre.

It's thought he intended to catch a bus or train home but is too late.

Instead he spots a parked taxi. He convinces the driver he's the one who booked the fare, but that the destination has changed and he has to go to Lisburn - right to McCullagh's front gate.

When he arrives home, he stops the stream and deletes the pre-recorded file.

McCullagh's arrest and release

McCullagh texts Natalie's phone and his friend Anne to further embed his alibi.

The messages suggest Natalie may be angry with him for drinking during her pregnancy and also that she may be having difficulties with her diabetes.

He also finds time to post a video review of a Star Wars Lightsaber toy.

That evening he travels to Lurgan, apparently to check on Natalie who no-one has heard from for almost 24 hours.

He calls 999 from Natalie's home, sobbing.

Over the course of a 10-minute call, emergency services are told "she's gone" and that there's "blood everywhere". He conducts CPR.

Prosecutors told the court it was all an act.

McCullagh tells police at the scene that he believes an "abusive ex-partner" was responsible.

He also tells them about his live stream the previous night. He is arrested at the scene but later released.

Police had accepted his alibi and, on Christmas Eve, told McCullagh he was no longer viewed as a suspect.

The former partner McCullagh had accused is also arrested and interviewed – he too has an alibi and is released.

That alibi was outlined thoroughly in court during McCullagh's trial, with the jury shown a video of him asleep in front of the TV during the World Cup final.

In the six weeks that follow, McCullagh acts out the grieving boyfriend.

He attends her wake, where he is given time alone with her. He visits her grave. He messages her brothers regularly.

He makes a tribute video montage from old home videos that is played at a rally in her honour.

He even goes so far as to leave his phone in the McNally family home, in order to record their private conversations.

After 39 minutes he returns to their home to say he has forgotten his phone.

He claims the recording was due to a glitch on the phone but the court heard he'd previously recorded a private counselling session of his former partner.

It is impossible to say the exact motive – McCullagh denied the murder, offered no explanation for the pre-recorded live stream and didn't take the stand during his trial.

But the court heard that in the months leading up to her death Natalie had been messaging other men.

Some of these messages were sexually explicit and she had told one of these men, the week before her death, that she was considering breaking up with McCullagh in the New Year.

The court heard it was believed McCullagh had accessed Natalie's phone and read these messages.

It was also told he'd previously been arrested for assaulting an ex-girlfriend after reading messages on her phone.

But jealousy goes only part of the way to fully explain the extent of the murderous plan McCullagh set in motion.

If this was a crime of passion, it was meticulously laid out, but eventually it was exposed as a cold and calculating house of cards that came crashing down.