I Catch Killers with Gary Jubelin
How to spot someone planning a mass attack: Ian Cherrington Pt. 2
13 Apr 2026
Transcript generated automatically by AI and may contain errors.
Chapter 1: What is the main topic discussed in this episode?
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Welcome back to part two of my chat with forensic psychologist and former UK cop, Ian Sherrington. In part one, Ian explained the indicators that can suggest a lone actor is planning an act of mass violence. In part two, we talk about how you can intervene before an attack. This is an important discussion. Ian Charrington, welcome back. Part two of I Catch Killers. Thank you.
We left part one talking about lone actors and mass killings and the type of things, the type of, call it indicators, red flags, warning signs that potentially we can look out for to try and prevent these attacks. Because This form of policing is different from the majority of policing in that it's very proactive.
If someone's got an ideology, when does that ideology, when do they start to act on it? When's that tipping point? We finished off in part two talking about some of those indicators. Is there any other things that you think we should discuss before we talk about what we should do to try and prevent these?
Yeah, so just to continue on the, we call them indicators or warning signs. Yeah, absolutely. So we talked about grievance, which is almost like a staple thing that you'd expect in most cases. There's some cases where mental health is the issue or dominates the issue. But even some of those, there's still elements of grievance, but some not. So it's just to kind of caveat that slightly, but...
We talked about tipping points, flashpoints. Those are things to be concerned about. And what I'd say about that is if you already know someone has a major grievance and talking about kind of taking action and then there's a major event in their life or around the world, then… that's when you should be concerned.
Whether you know them as a friend, family, or whether you're part of an agency, it's the same difference. Because once you get those things, it tends to accelerate. That's in the cases that we know about. We talked a little bit about preparation.
This is the idea that someone has to plan this and they might do it over a week or longer, sort of more meticulously, but often it's only a few days and you might get strange behaviors and reconnaissance. But one of the things I'd flag is that this is real world and online. So often you also get preparation online or comments online.
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Chapter 2: How can we intervene before a violent attack occurs?
But even so, I think it's concerning. And we'll talk a little bit about why. So the other side of this is, as you get quite close to carrying out an attack, a person like this,
they might start mentally preparing and this kind of comes in different ways but unlike a in a good example is a serial killer where perhaps the whole purpose of what they're doing is to stay secret and get away with it and carry on doing it this as i said at the start is like a blaze of glory it's their final moments but they know that they're gonna either die or go to prison you know they don't expect to survive one way or the other or continue their life as it is
If they're successful in what they're planning. And what's apparent is that that starts to dawn on them, the magnitude of it. It starts to affect them. And sometimes you'll see them behaving erratically. So they might, at those stages, late stages, start to kind of reach out to friends, family or agencies. They might start to behave very strange. Cases I've seen of people who
are pacing up and down, they're very stressed and no one understands why.
Chapter 3: What are the warning signs of someone planning a mass attack?
Or they might become very withdrawn and secretive and defensive and all these sorts of things. Obviously, these behaviors in isolation aren't necessarily that meaningful, but if you put it all together, that's when you start to see it.
And then the last part of that is particularly people... So if we talk about Islamist cases where there's this idea of martyrdom, so this idea of jihad or martyrdom where... the belief that they have is that they're going to heaven if they carry out this action or attack, then they're kind of facing a transition into a different space, right? Yeah.
But a lot of people are just scared of dying anyway. I mean, even if they're going to do this, they're still scared. Yeah. But they've also got to say goodbye. They've got to kind of leave people they care about, all their things. So you might see these sorts of behaviors where people are acting like they're leaving. They're acting like they're moving to another country.
Tithing up loose ends.
Yeah, this is sort of indicators or warning signs. And then the last thing that you notice around the late stages is this idea of leakage behavior. So this is an academic term that's been used for many years, and it can be direct or indirect. So someone might actually tell someone that they're going to do it.
Very often it's not like, I'm going to do it next week on this day at this place, because they want to do it. They don't want anyone to stop them. But they might say, I'm going to do something about it, watch the news, something subtle. And sometimes you get indirect behavior. So you get kind of almost like a run through of the attack or references to other attacks happening.
Look what they did there. I'd like to do that.
Fixation on keep bringing up one previous attack or something like that.
Yeah, so an attachment to that or a kind of interest. And then this last part, which is around this idea of being remembered. So if you think about the profile of a serial killer, they want to get away with it as long as possible. Sometimes when they're caught, they go to prison. But some of them do, you know, that's been seen before. They do kind of enjoy the notoriety.
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Chapter 4: What role does grievance play in violent behavior?
there's an opportunity for people to kind of put the flag up. And those sorts of behaviors are normally very close to the end, if you like, if they're going to go ahead. So it's really important to sort of think about why they might be saying those things.
It might seem strange in the moment, but if you consider everything I've said, and you have all those ingredients in one place, then that's when people should come forward and say, this is what's happening.
Okay. What you've described there, it's a broad range of behaviors. But in essence, what you're saying is a change of behavior. And the people that would notice that are the people that are close to them to start with. So there's an onus on people close. That change of behavior, I've seen that investigating suicides where people have taken their own life quite often during the investigation.
There's that change of behavior where they're making peace with people that they've had falling outs with before, or there's a calmness that comes over them. So I suppose what you're saying here, if we're going to combat, try to prevent these type of crimes, everyone's got a role to play. People that are seeing someone that they might be close with that's changing their behaviours.
And I take on board what you're saying also about threats of violence, if people are saying, because the world has changed. You might've got away with that 30 years ago. I'm going to kill this bloke. I'm going to do this. I'm going to do that. But we're all in a society that we're a little bit more cautious about that. So that is sort of stepping outside the norm, isn't it?
If you're talking about violence you're going to inflict on someone.
There's a truth to it that people do, you know, working in the police, people make threats, say things that they never are going to do or never do anything about. They do that. That is a thing. These are so huge, the devastation, the impact they have on people.
In the context I've given, I think if someone says that they're intending to do an attack like this, personally, I think every single one of those comments matters. should be reported because it might not be every time, but they really meant it. But at the end of the day, that's in their head. And often the ones that are successful, it's a strange word to use, but they, they often do that.
And it's, and you can see it, you can see it in the cases afterwards, you know, but it's too late then, right? It's, it's happened. And, Lots of people have been killed. So if someone is saying that they intend to do something of this nature, personally, I think that's the biggest warning sign for me. It might not be true every time, but it only needs to be true once, right?
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Chapter 5: How do online behaviors indicate potential threats?
That's why they've connected to these subjects or these groups. And so protective factors are kind of trying to address some of that. And it's not to kind of make out like they're necessarily victims or, you know, but it's in reality, This sort of thing, it's a social issue. It comes from social issues. That's what I believe.
And one of the most powerful ways to kind of actually stop someone and steer them away before they ruin their life and other people's lives is to kind of get involved with them and treat them with some support and protective factors to try and improve situations.
It might be their living situation, it might be their family situation, you know, abuse, things like that, but it might be simply a sense of helplessness and When I talk about this stuff, the lines aren't clear. I'm emphasizing children because children can get involved. The easiest way I can explain it is people would have seen that show Adolescence on TV, which is very powerful.
But it's this idea of parents having a child capable of something that you would never imagine. But also... When that happens, people start to sense that it's like something to do with them. It's their fault, you see? And these are very complicated things. And I think that they often mean that people won't step forward, particularly parents and families, because they're so concerned.
They can't quite believe it themselves, you know, that this person's capable of it. But obviously, if someone's got much further down the line, even if they're arrested, the whole thing is averted, which is huge. And so if they went all the way, it's worse. This is a difficult subject, but it's the truth. It's much worse to not intervene if you have a chance to.
So I take on board what you're saying, and I understand that it's something that should be encouraged, the intervention approach. We talk about young males because quite often this is the way it plays out.
Breaking it down into terrorist organisations where they see young males potentially as vulnerable, they're looking for whatever connection their life is lacking, they're looking for their tribe. Are these the type of people that get exploited? And if I just put it in the category of people that hold extreme ideologies, are these the type of people that they exploit to carry out their work?
Yeah, there is a range. And the modern evolution of this is generally young people are being brought into this subject online. They're doing it by themselves. If you go back some years, it's not that it doesn't happen anymore, but you do get these situations where adults, if you like, would groom or radicalize a young person and get them to do their bidding or do their work for them.
Over the years, I think what's happened is just a slight shift where people can be encouraged or even self-radicalize themselves. Even cases now where AI gets involved are in the middle of this. So cases where certain AI models will interact with an attacker... And can support their ideology. Yeah, like how to plan it as well. So it's a slightly frightening sort of evolution.
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Chapter 6: What is the significance of 'leakage' behavior in threat assessment?
There's a lot of information goes around, and particularly if you're a police officer, say you're a police constable, you've got a million things to worry about. What I'm interested in is tuning people in enough that they would see it. You know, they connect the dots because they've heard an input or a training input or something like that.
Or they've, you know, and this is the same for the community really, is that if you see things, it's a bit like, I always sort of try and, you know, let's take the example of, there was a big thing in London. We had a lot of bombings back, you know, 20 years ago or so. And there's always this kind of, if you see a bag, You know, you get the announcements, don't you?
Sometimes newspapers, and I'm sure you have that here as well. It's kind of tuned people into that. They'll go, there's a bag over there and there's no one here, you know. And I remember riding the tube after the 2005 bombings in London, the 7-7 bombings. And that happened on one of the train. It was the day after. And, you know, the people were shouting about that bag. It was nothing in it.
But it's kind of, it's the being tuned in so that you see it. If you've never heard of this or you've never thought about how it happens or what you might see, You're not going to react. But what I'm trying to do here is to make some of these warning signs a little bit like that bag.
So it doesn't matter if you're a police officer or you work for an agency or just a member of the community because it's not as simple as... it being a police problem, it stretches back. And so if you know someone or even if you don't and you hear them talking about this sort of thing, it's the equivalent of that unattended bag.
You pick up the phone, you go online, you call the police or you call someone or you tell somebody, maybe you tell friend, parents, family, whatever, you're online and someone's talking like this. That's the way I would see it. Because most, like the bag, most of the time it's nothing. Yeah. But this is like a metaphorical, right?
But I do understand what you're saying because we all became aware of that bag situation. Anytime you'd walk through an airport, public transport, any locations, and if you saw a bag there unattended, you're looking around. So we did become aware of that situation.
And think about it like, I mean, these sorts of things I think about, you know, obviously lots of people don't, you know, it's probably not great. But nowadays a lot of these attacks are rudimentary. They're knives in cars and things like that, right? So you're not going to see necessarily as often maybe nowadays the bag, the bomb and all this. Not saying it won't happen or never happen. Yeah.
What I'm trying to say is some of these warning signs, which are kind of behaviors, are your metaphorical bag, unattended bag, a combination of them. But particularly this idea of leakage behavior, particularly if someone actually says that they're intending to be violent because of some issue, they've got grievance, ideology, cause. That's what I would try and connect to it.
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