It all appeared to have been broadcast live, as he had claimed, and McCullagh was eliminated as a suspect in the police investigation.
However, it emerged at a court hearing this week that the 32-year-old’s story has since unravelled after police dug deeper into his alibi following the discovery of new evidence by investigating officers.
The police officer leading the murder investigation told the court that extensive technical examination of McCullagh’s computer devices by cyber experts had indicated the YouTube footage was pre-recorded and played out as if it was live.
PSNI Detective Chief Inspector Neil McGuinness told district judge Rosie Watters that while McCullagh denies involvement in Ms McNally’s murder, he admitted during questioning this week that the purported livestream was pre-recorded by him days earlier.
The YouTube video uploaded on December 18 by McCullagh, who uses the name votesaxon07 on his channel, remains on the video website.
It is called The Violent Night Christmas Live Gaming Stream (Streamy Goodness).
Following this week’s court case, hundreds of comments have been left underneath the video. Some of those commenting have called for the recording to be taken down.
On the footage, McCullagh is pictured wearing a Christmas hat in what appears to be the living room of his home in Lisburn.
After a music introduction plays for two minutes and 45 seconds, McCullagh appears on screen and says, “Hey, and we’re live. Hello everyone, yeah a little bit out of the blue this, isn’t it?”
As he adjusts the camera on his computer, he again stresses the fact the broadcast is allegedly going out in real time.
“That’s the fun of being live, isn’t it?” he says.
“Hello to all on this glorious Sunday evening. Yeah, so I just thought why not, I am going to do a livestream because this day next week is Christmas. So, what more could you want for Christmas other than an evening with your old pal Stephen?”
Before he starts playing the game Grand Theft Auto, McCullagh tells viewers that because of problems he has been having with his computer equipment he will not be able to “check the live chat” on the stream.
He says he could check the live comments on his phone, but adds that he hates livestreams where the host just “sits and read comments”.
McCullagh proceeds to play the computer game for six hours but takes a number of short breaks.
During the broadcast, which police described at Thursday’s court hearing as a “monologue”, McCullagh checks the time on several occasions.
At the end of the broadcast, McCullagh, who is seen to drink alcohol throughout, wishes viewers “Merry Christmas”.
The Sunday World contacted YouTube to enquire if they had been asked to remove the video.
A YouTube spokesperson said: “Courts and government agencies around the world regularly send us legal requests. We have established processes in place to review these requests closely to determine if content should be removed because it violates an applicable law or our policies.”
The Police Service of Northern Ireland (PSNI) was asked if they had the necessarypower to ask for the video to be taken down, and if they had made such a request.
In response, a police spokesperson said: “As a matter of course in investigations of this nature, detectives will secure a Preservation Order for any social media sites they deem relevant.”
McCullagh, who turns 33 later this month, spent a lot of his time reviewing toys online and describes himself on his YouTube channel as a “massive man child”.
His love of toys and gadgets led to him appearing on a hit TV show several years ago.
The Lisburn man was part of a team which appeared on Robot Wars in October 2017.
In the BBC show, teams of amateur robot enthusiasts battled it out over a series of rounds in a purpose-built arena, aiming to be the Robot Wars Champion.
McCullagh and his fellow team members, Shane Swan and Anthony Murney, created a robot which they called ‘Push to Exit’.
In the programme, McCullagh is seen working on the robot as presenter Dara O Briain speaks to team leader Swan.
However, the alleged killer’s appearance on the show ended in embarrassing failure.
