(What? TSA's job isn't to protect marathons? Silly patriot, do you want to let the terrorists win?)

Please read some history.

> These events include Mr. Mukerjee becoming further agitated and aggressive after testing positive for explosives, as well as him repeatedly reaching for his not-yet-manually-searched bag.

> However,multiple statements by TSA personnel reference Mr. Mukerjee repeatedly grabbing for his bag after he was told not to touch it.

> While false positives are not unusual for ETD, it is unusual a person and their items could fail so many times using different testing equipment.

What would you have done in a situation like this, when people's lives are at stake and it's your fault if something goes wrong and someone gets hurt?

The agents did several things that escalated the whole deal, things which a cadet would have immediately understood. To quote just a few:

> These events include Mr. Mukerjee becoming further agitated and aggressive after testing positive for explosives, as well as him repeatedly reaching for his not-yet-manually-searched bag.

> However,multiple statements by TSA personnel reference Mr. Mukerjee repeatedly grabbing for his bag after he was told not to touch it.

This is wrong on the following levels:

1. The first fucking thing you do when you detain someone is explain them why they are detained, how long they will be detained and -- if they have not actually broken any law and are there for preventive action, what you are doing in order to prevent it. If you exceed this period by the most infinitely small amount of time, you immediately tell them why it is taking longer (in some civilized countries not doing this is reason enough for the state to start selling politicians' kidneys to pay damages). Basically, what the dudes should have done was say: "Hello Mr. Mukerjee, we have to detain you on the basis of <whatever law they are doing it on> because we have suspicions that you might try to harm the passengers on board. We need to check a few things up, this will take <how much fucking time can it take to check a stupid suitcase and a handbag>. I understand this may sound outrageous to you, but we need to make sure." It's particularly important that you use normal-sounding words and sentences in an active voice. Someone who isn't a regular jail offender will most likely be panicked enough to to understand a word you're saying if you start throwing shit like "we believe you might be a threat to the safety of the crew and the passengers of the vessel".

2. If you don't want people to get agitated, you don't offer them external triggers. If you want to conduct a search, you immediately remove all the bags after conducting a thorough inventory of it in the presence of the guy you're searching. "Mr. Murkjee, we need to search your bag <on the basis of whatever law allows us to do that without a warrant>. Can you please tell me what's inside? We will have to remove all items in another room, we need to make a list of the items inside to make sure you get them all back". Of course people are going to get nervous if they are in danger of losing their work. They kind of depend on it to eat. If you don't remove these belongings, people will naturally keep peeking at them and grabbing them and insisting on touching them because they're afraid. It's a natural reaction.

3. If you detain someone for longer than half an hour, you provide for their needs period. You ask if they need water or a snack. If they're guilty, they'll have a long time to be thirsty and hungry in prison, but there's a long way before that. You do this for two reasons that you hear about in the first six hours of training (if your instructor is slow, it can probably take as little as four...). First, basic sensations of thirst and hunger amplify the sensation of fear. Second, dehydration and low blood sugar levels heighten the symptoms of fear and panic, like anxiety and shaking.

4. When someone tested positive for something, you either don't tell him and get on with it on your own, or you tell him and ask for an explanation. Maybe the dude visited a friend whose kid got a chemistry kit as a present and splashed it all over the table in the living room. Either tell him "Mr. Murkjee, you tested positive for di-hidrogen oxide, a substance we believe may be explosive. We need to conduct a further search through your items -- we have people working on that right away so that you can be back on your trip as soon as possible, but in the meantime, do you know of any way in which you could have come into contact with this substance?". Either do that, or just tell him that their preliminary tests showed traces of an explosive substance, we need to search your items to know for sure if it can be dangerous. In both cases, tell the dude how long it takes. People can have a panic attack just because of missing a flight, can you imagine how awesome it has to be to have someone who carries a gun drag things along when you have a plane to catch?

Bonus things the TSA folks fucked up:

5. If someone wishes to go but you haven't finished your procedure, you fucking tell them why and explicitly mention what you need to do before clearing them. People who fly have no way of knowing, and particularly no reason of knowing the whole procedure. Telling him he can go, but the bag stays was a major fuck-up that is usually reason enough for disciplinary action in a normal police force. You don't just tell people they can go without their items. The correct thing to do is say something along the lines of "Before clearing you for leaving, we need to check your bag, in case it may contain items that could be harmful for the passengers in the terminal. This will take <X minutes>, once we're done you're free to leave if you wish".

6. There is no such thing as a "limbo", not in any sane security procedure. Someone is always in one of three possible states, and if he goes from one to another you immediately mention it: he's either detained (for a definite or indefinite period of time), free to go after a procedure is finished (all suspicions are off, but there's some compulsory stuff that needs to be done -- e.g. you're sent home from the station, but you still need to get the receipt that confirms you received all your items from storage before they clear you to leave) or you're free to go. "There is nothing wrong with you but you can't leave" is a form of abuse period. It does not matter if things aren't that way: what the man sees is what you're telling him. There's no way a boarding passenger knows the whole procedure, so that he can go like "Oh, there's no need for me to worry... I'm ok but they can't let me leave while my bag hasn't been searched. I can't just go and mingle with the people who have been cleared to fly while I haven't, since I might stealthily hand them a knife or a pack of explosives after they've gone through the security check."

7. If the reason you are detaining someone is a subjective one (i.e. the dubious-guy-spotter said he looks dubious), you still need to provide a reason for detaining him. If you don't, the dude will naturally think you just picked him at random, which he will -- again -- perceive as a form of abuse.

tl;dr There are some basic things you need to in order to tell if the person you're talking to is being aggressive or giving inconsistent answers because he's preparing to carry out a criminal offense. If you don't do them, you fuck up your screening process.

Being under pressure is not an excuse for not doing a job you're supposed to do under pressure.

Full disclosure/source: I wanted to spend an year in a computer security-related position for a state institution in my country of origin, and had to take a course on this. My memory of the details is fairly dim, I hope I haven't trashed anything significant.

From what I can tell this has even been emphasized lately, now when I opt out at SFO they have me bin my stuff and wait until they are ready to pat me down before running it through the x-ray. Once it has been x-rayed they put my belongings where I can see them (but are quite clear that I shouldn't reach for them) while they do the pat down.

When I took the course I mentioned in my post above, the explanation was along these lines: when you want to check someone who carries a bag, you need to remember that he has certain expectations about the safety of his belongings. If you're in a public place, it's reasonable that you never remove the belongings without assuring the owner that they are safe and well-guarded. So when you stop a gang of half-drunk teenagers on the street, you don't ask them to drop their backpacks on the sidewalk and then go ten yards further to search them. You ask them to leave the backpacks in a single place, right near them, and while your colleague searches the backpacks, you keep an eye on the dudes.

That's the common-sense thing to do: no one would let their bags two meters away from them in an airport, even if they kept a constant eye on them. You can't just expect someone to be okay with leaving them god knows where.

If you ask people to put their belongings away in a designated area, the correct thing to do is to have that area placed well away from any passers by and a guard near it. That way, you can tell the owner something along the lines of "Please put your bag in that bin over there; don't worry about it, it won't be stolen -- that man staying guard there isn't leaving, he's there to make sure you get it back just as you left it. We need to ask you a few questions, and then we may have to search your bag. we'll search it in front of you to make sure no one steals or breaks anything, and if all checks out okay, you're free to go. Any questions before we start?"

As our instructor mentioned it, it's really important -- especially in places like airports, concert arenas and whatever -- where you might expect one terrorist every two years and ten thousand disoriented folks with a scare of flight who triggered the bomb detector with their cheap after-shave every day -- to treat people without hostility, with an attitude of collaboration, not suspicion. Very few travelers are at fault for the US' foreign policy (and those that are probably don't go through the whole TSA hell), so it's not their fault that some guys from the Middle East want to blow up their planes. In places like these, you want to treat people so that they can say "yeah, I know this is inconvenient, but the guy is only doing his job", and because they are already under a lot of stress, you want to make sure you don't heighten their fear.

Searching the bag in another room has too much abuse potential. If travelers let bags out of their sight even for a few minutes the TSA could easily steal or break anything of value in there with no accountability. So the existing procedures mostly don't allow that - searching has to take place in the presence of the passenger.

That's actually the recommended policy in most cases (not only TSA), for several reasons. One of them is the one you stated; another one is that suspicions related to a particular item can be cleared more quickly by just asking the owner, and if you do it right, you can also get various hints about anything illegal (e.g. the guy is ok until you find the hidden pocket).

There's only one case I know of where searching without the owner's presence would be legitimate -- if the exact testing equipment and procedure must not be divulged, for fear it might reveal vulnerability. This is a form of security by obscurity though, and a sane system shouldn't need that. I'm sure this isn't the TSA's case, but there are cases where it can be an option -- for instance, in an underfunded law-enforcement system that can't afford sufficiently broad testing equipment. In their case, introducing further delay in the obsolescence of their equipment probably ought to be understood. This comes in various other incarnations -- e.g. if you suspect the bag may contain dangerous substances, you typically want to search it in a special, sealed room.

Nonetheless, if searching is done in another room, that's always done according to a procedure that ensures accountability: you ask the owner to tell you what's inside, make a list of everything there, and ask him about the working condition of every gizmo inside. The proper way to do it is with a constructive attitude -- if the bag is stuffed with various items, you assist the owner by taking the items one by one. You don't let him touch them, in case he might sneak up that bag of TNT when you aren't looking, but you help the guy -- if he's got thirty gizmos inside, it's only natural he won't remember them all. But in this case, the search is then conducted by someone else (in order to avoid subjectivity issues -- e.g. the dude has a vintage handheld radio from his grandfather, it's filled with explosive but when you do the search, you test it superficially because it's a vintage radio, what the hell...)

Specifically, I think good directions would be:

1. Driving away the "law enforcement" culture. Are members of the TSA staff registered as policemen, assigned to a station, going through police academy and under the rules and discipline of police training? If not, they aren't law enforcement and shouldn't be treated as such, and should either a) be disallowed from conducting any kind of search without the supervision of a policeman or b) covered by the same regulation as a regular policeman. You can't have people do police stuff with non-police discipline, eschewing the checks and balances law enforcement has in order to make sure it enforces, you know, the law.

2. Providing immediate legal counseling as soon as you step into a private room. Large crowds tend to be a good protection against abuse. Once you step into a room, anything more than searching through personal items should be covered by a lawyer, and people should particularly only be questioned only in the presence of a lawyer. This is because a) the lawyer would be able to assert the rights of the person being questioned and b) the lawyer would be able to explain what's happening in layman's terms. When a particularly uptight ex-postal employee who just discovered authority exceeds gets nasty, a third-party reminding him he's stepping outside the law works much better than the person on the receiving end of his newly-discovered authority asserting his rights -- risking to be regarded as "aggressive" and "overly-assertive" by someone whose most important previous responsibility had been making sure stamps are correctly positioned on the envelope.

3. Explicitly encouraging and rewarding correct behaviour from TSA personnel, while at the same time applying serious disciplinary action. Let's be honest here, there's a large enough supply of unemployed people who can search a bag that you can afford discharging abusers, and sufficient public frustration that you can afford offering the occasional bonus to people who go out of their way to clear up misunderstandings.

So maybe it's finding something true. BFD. You look in the bag, verify there's no explosive there, and let him through.

Maybe the bag had fireworks in or near it at some point. Or magician's supplies. Or a chemistry set. Or any number of other things. There are a dozens reasons why a bag might actually have been near explosives or chemicals that are similar enough to explosives or explosive precursors that the test would correctly show positive.

Nobody cares whether the test result was an error or a "correct" reading based on something that IS NO LONGER IN THE BAG - either way, you let him through. Why the hell not?

The sad truth is that the terrorists here are us. The primary reason nobody has blown up a plane recently in the US is that nobody is TRYING to blow up a plane in the US. If somebody were seriously trying, they'd have done it already.