A man has been arrested in Dublin after a heinous video was posted online this week explicitly threatening President of Sinn Féin TD Mary Lou McDonald and Garda Commissioner Drew Harris.

“Gardaí have arrested a man in his 20s as part of their investigation,” a spokesperson for An Garda Síochána told IrishCentral on Thursday afternoon.

“The man is currently detained under Section 4 of the Criminal Justice Act 1984 at a Garda Station in the DMR [Dublin Metropolitan Region].”

The Special Detective Unit arrested the man in south Dublin during a search of his home, according to the Irish Examiner, which added that the man was arrested on suspicion of making threats to kill or cause serious harm under Section 5 of the Non-Fatal Offences Against the Person Act 1997.

Multiple outlets reported on Thursday that the man who was arrested is known to Gardaí.

Security sources, however, told the Irish Examiner that the man is not believed to have the "capacity" to carry out the threats he made, but they are concerned the video, which has been widely circulated across social media platforms, could influence other individuals.

In the video circulating on social media and seen by IrishCentral on Wednesday, a man wearing a makeshift balaclava films himself responding to the recent disorder in Coolock, north Dublin in an expletive-laden and threatening tirade.

"Petrol bomb the f--- out the lot of them, lads. Get up," the man says in his video.

He goes on to describe Garda Commissioner Drew Harris as a "prick" and encourages viewers to "Take his whole throat, lads. Take Drew Harris's throat off."

He added: "F--- Drew Harris. He'll be getting shot. He'll be getting f---ing blasted, I swear to god on that. He'll be getting shot before the end of the year."

He continued: "And see Mary Lou? I'll shoot her meself for free, I will, yeah. I'll do her for f---ing free, I will, yeah.

"F---ing little rats."

The man concludes his video by saying "Gavin Pepper for f---ing President. Get up."

The video was reportedly posted to the man's personal TikTok page which denoted his name and showed his full face in other videos. The video has since been shared by various other accounts on different platforms.

Speaking on Newstalk Breakfast on Thursday morning, the day after she publicly condemned the video, McDonald said the threat against her “speaks to something much wider in our society, and is frightening.”

The Sinn Féin leader said that in her role, she understands that she is susceptible to commentary and criticism, but that “every line has been now crossed” with this week's online threat.

“This is just the latest escalation in something that I think is really dangerous, generally, and that I know has been very deliberately targeted at me, and I’m sick of it.

“I hadn’t said much publicly throughout this year about what was going on, but once there is a direct threat made - openly, brazenly broadcast on social media - that a person will shoot you, that they will take your life, and that they feel comfortable saying that, broadcasting it, and announcing it to the world, clearly that puts you in the way of greater danger, and I found that frightening.”

McDonald said she chose to speak out after the threat in terms of her “own personal security" and also because “it is not on.”

“It’s me this time," McDonald said. "It could be anybody else.

"It is not acceptable in our society that people feel at liberty to throw their weight around like that and threaten to kill democratically elected politicians - or, by the way, anybody else.”

McDonald, who noted that the matter was being investigated by Gardaí, said that “there have to be consequences for these kind of actions,” adding that “it’s not because I’m some sort of special category of person. I’m an equal citizen in this society and my safety is on an equal par with everybody else's.”

Regarding the person who made the online threat, McDonald said: “The person who issued this threat against me spoke also about the issues around immigration and protest. He is part of that small section of Irish society that has chosen to be toxic and violent and disorderly and hateful, and they have to be faced down.

“And, at the same time, the wider section of many communities who are not racist and hateful and all of those things but who are concerned and have not been engaged properly, who don’t have confidence in the way in which immigration, in particular, is being managed at this time - we need to engage that section of the population and talk and listen, and listen and talk, and lead.”

McDonald went on to say that the TikTok video with the threat against her and Harris should not have been permitted to remain live for so long.

After the arrest, RTÉ News reported on Thursday the video which was originally posted on TikTok has now been taken down from that platform but remains in circulation on Facebook and X.

TikTok said on Thursday afternoon that the video violated its community guidelines which prohibit violent threats and incitement. It also said the content had been removed from its platform and the account banned.

Meta also claimed the video had been removed from Facebook, but RTÉ reported that they were still able to access it through the site and it is also widely available on other social media platforms.

IrishCentral was also easily able to find the video on X and Facebook on Thursday afternoon, though it had been shared by accounts slamming the man and his threats.

RTÉ News added that neither TikTok nor Meta would say how long the video was on their platforms, why it was not taken down immediately, if they were cooperating with the garda investigation, or whether their content moderation and security procedures have proven to be extremely weak in this case.

Both social media companies claim they do not allow violent threats, incitement to violence, or promotion of criminal activities but gardaí say criminal gangs use these social media platforms for organised crime activity.