How can we catch an invisible man?

Question

Some Background

The government is really, really good at catching people as we learned here and here. But as logic would dictate, there is always someone better. In this case, an invisible man. Unlike Dave or Eden, we know almost nothing about this new threat. After catching Dave and negotiating with Eden they have made the world aware that there is a third one; an invisible man named John. The united nations agree that he must be stopped, but how do you catch what you can't see?

A Few Details on the invisible man

• We know that he currently lives in America, though he could leave at any time.
• Dave and Eden allegedly only know of John through messages they send each other, but both of them give different answers on why they send these messages.
• From decoded messages, we know that Johns main motivation is a hatred and paranoia for the governments of the world.
• John is your average conspiracy theorist, he stays at home, steals whatever he needs and works out who else has 'powers'. For all intents and purposes, he is the self made leader of these strange people
• John does everything over the internet, but he refuses to use any website not in the deep web.
• As a conspiracy theorist, he has cut off all ties with his former friends and family.
• As a conspiracy theorist, he has stockpiled enough supplies to cut himself off out of human society for 5 years.
• While John is invisible, the effects that he commits are not; for example, if he steals and eats an apple, people will see the apple hover and will see the apple disappear into the "air"(his stomach)

The Rules

• The governments best scientists have become desperate and are willing to spend whatever it takes to bring John into custody for further study.
• They do not want to kill John, they just want to bring him into custody.
• The solution cannot result in any human casualties.

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Using the above information how can the governments of Earth catch John?

Answer 1

John is the ultimate agent out there.

You do not need to bring him in. All you need to do is manipulate his behaviour. Just plant the stories that you want to be known. Once the carrot is taken, reel it in. As soon as you are able to make him believe what you want, you can make him do anything.

A team of the best agents, hackers and profilers should be able to do this. Plant some good stuff for him to grab. Guide him to a honey-pot with tasty titbits of intelligence. Some old dossiers like Area 51 should help building credit. Manoeuver him to a nice spot to set up a top notch secret base. It is of course pre-seeded with monitoring equipment.

Now you have your shop running. John will detect, recruit and train new talents for the government to use in an ultra covert way.

Looks like John will be able to run the new "No Such Agency" on a far smaller budget than regular government agencies. Pretty nice bang for your buck. Who needs a conscience?

Answer 2

This answer was written before John's supply stockpile was added to the question. The answer looses some of its applicability now that John doesn't have to leave his home.

A quick upgrade to the nation's ATMs is all that is needed. Currently, each of those wonderful money machines has a ccd camera pointing out at the world, watching everything that goes by. It's a small stretch to imagine that a desperate government with a first world budget might have more than occasional access to the things those cameras see.

Invisibility is John's greatest strength, but it is also his greatest weakness. All you need to do to catch him, is trade out those ATM cameras for hybrid devices which constantly switch back and forth between visible light and infrared. For a half-second, these new camera sample heat radiation and then for the next half-second, visible light.

...and everytime they see a man shaped blob with the infrared, but don't see it under regular light, report the sighting to your local governmental department of paranoia.

Once you know what city John is operating in, it is time to upgrade all of that city's traffic cameras and police car dashcams. From there, it is only a matter of time before his current sleeping place is known.

With that much information, catching him should require nothing more than sleeping gas and gas-masks with built-in infrared lenses.

Answer 3

Infiltrate whatever network John associates with.

John feels he's a leader of what he believes to be some sort of political resistance. In order to do this, he has to communicate with other people. So the government needs to use agents who join that organisation, communicating with John on the Deep Web. As the agents gain John's trust, he may eventually let some piece of helpful information regarding his location slip.

Set up Tor nodes

To access the Deep Web, John is using Tor (or an equivalent service.) Since those who are trying to catch him are a conglomeration of all the governments on Earth, they have a lot of resources. Anyone can set up a Tor node. Using a wide variety of covert (seemingly harmless) NGO's and philanthropic front organizations, they should set up a number of nodes (entry, exit, all kinds) that is so large that they now (covertly) control the vast majority of Tor nodes. Having control of these nodes, they will now be able to compromise John's communications. Sooner or later, John will be routed through nodes that are entirely controlled by the government(s). Using their technological expertise and massive resources, they will then be able to find his real IP and thus, his location. If he is using a normal proxy in addition to Tor, they just say John is a terrorist and get a warrant to get his IP from the proxy provider.

Actually catching him

Once you know where John lives, dispatch a special team with infrared vision goggles. These googles will see John based on his body temperature. You don't just burst through the door. Being aware of threats, John might have an escape plan. You need to first figure out exactly where in the house John is. To do this, you could post spies with infrared binoculars all around the house, trying to see his body heat. You could also dispatch silent drones with heat sensors to attach themselves to the walls, but this might be risky. What if John goes outside and sees one? If John is sufficiently careless, you may, even without infrared, see doors, food items, his personal possesions, etc. moving around in the air inside.

Once you know where he is, you need to burst into that very room. Bring a massive "water-bomb" that gives a blast of watercolour paint, painting everything in the room, including John, red. Or you could follow the water with an explosion of flour, making everything in the room covered with flour.

That should take care of his invisibility for a little while. Then, handcuff him to the inside of the car and drive off. Obviously you need to have him locked up/handcuffed for the rest of his detention.

Answer 4

John is no more difficult to locate than any other human since he has the same needs and wants. Any man tracker can use normal methods to fid his location. The difficulty is the final moments of apprehension since you can't see him with visible light. Agents unaware of this will be hard pressed to catch him if he attempts to flee. Agents aware of his invisibility, but unaware of how to detect him with some other method, will have to set up a shoulder-to-shoulder cordon around his location, physically block all entry/exit points, and watching out for suspicious movements of objects (curtains, windows, triplines, etc). They can still hit him with bean bag rounds, tasers, tear gas pellets, etc if they saturate any area but they have to know ahead of time to do this.

If they have the means to detect him (infrared googles, sensitive microphones tracking his heartbeat, sensors that "smell" his sweat or CO2 emmisions, paint distributing munitions liberally applied, adhesive foam spray in the ground, etc) within a limited area then he can be easily corralled and captured since presumably he will not be able to interact with any object or protective device (gas mask, armored vest, firearm) without revealing himself to long distance interception (drug dart firing rifles, tasers, etc).

This will all require lots of manpower, however. Aside from thermal imaging most detection methods are laborious to use, of relatively short range (FLIR can be used by drones or helicopters though), or require time to set up and deploy. John's main advantage is short term escape.

His long term survival relies on his ability to network with like minded individuals, access money/supplies, and be able to blend in with everyone else. If he can't fake a physical presence he will have to do everything he needs over the phone/internet/or through a hired proxy. These methods are far more trackable than doing them in person since electronic methods can be monitored and using a proxy adds complexity and opens him up to being turned in. His SUPPORT NETWORK is his greatest vulnerability as he himself is greatly hampered due to the need to disguise himself in order to interact with ordinary people.

Answer 5

All the answers about tracking John by matching visible light optical with thermal or infrared is that the OP mentions "While John is invisible" which suggests he turn his invisibility on and off. If John is smart enough to walk around visible it will be difficult to spot him using comparative imagery.

However, government buildings and facilities can be safeguarded against him sneaking in by using a much simpler version of this same technique. Photo-electric beams across doorways and entrances and set up in pairs with one beam visible light and the other infrared. If John blocks the infrared beam but the visible light beam passes right through this can trigger a silent alarm.

As for catching him Fiksdal's infiltration of the deep net sounds like the most sensible approach. If he never comes out of his house and abjures society, but he would be dangerous if he did do so. The main problem is that he's an invisible man who, paradoxically, nobody sees. The answers that suggest he can be tracked if any other malefactor are essentially correct. Catch him through his normal needs of supplies and the communications he uses to marshal his agents.

It's only the actual laying on of hands to capture him for sure that has problems since he can become invisible. Stun grenades and water colour bombs might do the trick. Disoriented by the stun grenades he might lose his invisibility, but if he was invisible the water colours might soon disappear too if he can ingest apples and have them vanish.

Answer 6

https://www.youtube.com/watch?v=w-YLJ-pHRhA

It sounds really annoying, but it can give you some ideas . Like luring him into a building, then activating the fire sprinkler system and then watching a blob of water running around.

Answer 7

Why not attach a infrared camera, and a normal camera to a drone ? If the images don't make sense (that is, the normal camera can't see anything out of the ordinary, but the infrared camera does) then you have found your invisible man !

This will take a long time though, because if the invisible man stays inside all the time, then it will be hard to find him that way. Also finding one dude in a city is also hard (though it's made easier by the fact that he obviously wont go into crowded places - otherwise people will constantly bump into him, so they drones should focus on areas with less people).

This way, you don't have to send spies or all sorts of elaborate plans, just a lot of drones. (High up, so he wont realise there are tons of flying machines in the sky)