Acolytes don't really have any official authority themselves, only derived authority from their master. Also an arbite's remit is really only crimes amounting to either treason or heresy is rigidly structured into (regional/planetary) jurisdictions.

Most recruited arbites are likely out of their official jurisdiction too.

Without offical orders from the arbites to support the covert operation he was caught for (which can be verified with a superior) or direct inquisitorial influence he will be in big rouble as he is essentially a rogue agent until he can prove useful enough to get a new ident or a pardon from his master.

Notably this is a great time for you to reign him in by making him a priority target of local enforcers wanted posters with dead or alive bounties offered, the lot. Force him to play in a more subtle manner or face the unbridled wrath that cops reserve for a cop-killer.

Well, the Arbites are to the Magistratum sorta what the FBI are to the LAPD. They can certainly flash badges and give them some "juris-my-****-tion crap", but they cannot commit blatant crimes and just flash their badge and expect to go free. Neither are they justified in a murderous killing-spree just because someone lower in the order of things don't jump to their orders.

Now, this comparison isn't perfect, as the FBI do not have the sweeping powers that the Arbites do. The Arbites can perform field judgements and summary executions for pretty much anything (see some crazy examples in the Book of Judgement), and are more like Judge Dredd than the actual FBI. But the principle holds: The Arbites polices the Imperium, and enforces the Lex Imperialis (which means dealing with cults aiming for secession and officials withholding tithes mostly), while the Magistratum enforces local (planetary) law.

Oh dear...

in my books, the killing of the Enforcers crossed the line. By Default, the Arbitrator broke the law.
Even if he would have produced some document (a Letter of Investigation or something) that would have ALLOWED him to forge documents or act as an imposture, that does not mean that you are in a form of Emperor given right to kill people.

Who can bring in an Arbitrator?
Basically, another Arbitrator. And even with the Magistratum and the Aribtes being at Odds, the next troopers to face the characters will be Arbitrators. They will attempt an "adress and capture alive" Approach first. At least, that is how I as an GM would handle things. But if the Player is reaching for a gun again things are over and while his character might still be on the career pass of an Arbitrator, he won´t be an Arbitrator legally no more. An Arbites kill squad will be after him from that Point on.

What happens if the character is turned in? How is the Situation to be solved?
The authority that can legitimate the characters Actions are the Inquisition. They have a VERY open and large presence on Scintilla (the Tricorn Palace). If the Arbitrator is put into a Holding cell and Claims to be part of the =I=, an interrogator of the =I= will Show up. Possibly one of the players´s Inquisitor. things will be handled..after a day, perhaps two.

The Inquisitor of the character should have a word with him (or one of his Senior acolytes should). The local Arbites Proctor will have a word with him for sure. Both asking sternly why he killed the Enforcers. Why he did not allowed them to capture him and solving the Situation like it is solved now "but without the unnessary death of three servants of the Imperium"

Punishment: Suspend him from Services as an Arbitraor (at least fo rthe cause of the next adventure; things will Need t be settled). In Addition, the Inquisitor might want to think about some measures. Perhaps he is officially put under the command of another cell member who is more responsible. The Arbitrator is not allowed to act without his sanction.

All I can think of while reading this is that the noble house that the arbitor plus friend tried to imitate are going to be rather pissed about now and send some of their most loyal assassins out to eliminate the two and all that they know and hold dear... and that they have some of the rival houses assassins after them as well. "Hey did he not say that he was of house (insert name here)... he is awfully simply dressed today... and his guards does also have less armour. I have never heard about him before, but an easy pray is an easy pray."

Rank and hierarchy is one of the most important things in the 40K world (from my point of view), the solid block from where it all stands, so just thinking to try to fake yourself as something bigger than yourself is strict no no. I as a GM would ask him how his character would have reacted if a person that they thought was part of their cell turned out to be an outsider, and then what there makes him think that he can pull it of and be fine with it, but different GMs different play styles.

As to what there would happen next, the big I would be pist, the nobles would be pist, his fellew arbiters would properly also be rather pist if they heard about this incident. Gregorius suggested to take away his badge, something that I think would be rather fitting both as a punishment and as a lesson for what rank he actually have, for when he get his badge back will it be a smaller one, given to him with a lot of paperwork to sign, and someone watching over him. Had a psyker done something like this would he have gotten a nice bomb collar, but they do not really match the arbites style... so what about a nice pair of bracelets, ready to blow his hands of if he ever uses them to something that just smell like breaking the law without having gone trough oceans of red tape for the permission. A little negative modifier to Fel when he talks with people that knows what he have done would properly also be in place, but be careful about misusing that too much, the imperium is large after all, and he is just a drop in the ocean.

With that said and done, whatever you do to punish him, try to make it a hook for something that can be rewarding again later on if he behaves. There is nothing as bad as getting punished time and time again when you have learnt your lesson, especially if you didn´t knew that there was a lesson to learn to begin with.

Playing Devils Advocate for a moment:-

This all hinges on why they were impersonating the nobles. If this was a useful proportionate action to further their lawful investigation then actually, counter intuitively (may the GM gods strike me down...) the Arbite probably has a point.

Imperial law doesn't really suffer the excuse of ignorance. So the magistratum reason for detaining the Arbite is pretty much irrelevant. As long as he explained it was part of an investigation and he can prove this afterwards then he probably hasn't broken the law. Furthermore of all the Acolytes the Arbite does actually have some genuine authority. If it was a heresy against Imperial rule it falls in his jurisdiction.

However his Inquisitor probably won't be happy. Just from a political point of view it is embarressing, plus this situation arose because of the Arbites failure to do his job properly.

In addition if the acolyte is using Arbite authority then the Arbites are within their power to call him in. He can't supercede this by simply waving a letter from his Inquisitor at them.

The Arbites are very powerful but it is a different kind of power to the Inquisition. The Inquisition are powerful because basically they can do what they want, when they want, to whom they want. In a society of strictly imposed rules, duty and boundries this is very very scary. Imagine someone appearing on TV in outlandish dress declaring all the world leaders of Earth heretics (literally those words) and within 48 hours all the major world leaders had been black bagged and dissappeared . The figure is not seen again leaving only a few scattered YouTube videos that pretty quickly were removed to remind people of what happened.

This is the Inquisition.

The Arbites by comparison are very well known. They are powerful because they physically have the weaponry to enforce the law and more importantly have the right to enforce the Imperial law. However as soon as an Arbite stops enforcing the Imperial law, and they must always be clear exactly what law it is they are enforcing, then they have no authority.

Imperial Law is very specific as well. Two guys get in a brawl and one stabs the other. This is local not Imperial law, Arbite has no authority.

Noble raises an army to overthrow Imperial Governor. It is well known his stated intention is to take over Governorship himself, remain part of the Imperium and recompensate the Administratum for any disruption this is an internal political matter. Arbite has no authority.

Some good points in the above, though I would add two things concerning my own interpretation:

Two guys get in a brawl and one stabs the other. This is local not Imperial law, Arbite has no authority.

Although I would say it very clearly does not fall into the Abites' job, I don't think there is anything stopping an Arbites from interfering anyways, possibly just shooting the stabber on the spot and then moving on. Local enforcers are making a scene at the Precinct? Then they are interfering with the Arbites' duty.

I would deem it reasonable, perhaps even expected, that his superior formally reprimands the wayward Arbites for neglecting his duty in sight of some minor crime he's not supposed to police, though.

Noble raises an army to overthrow Imperial Governor. It is well known his stated intention is to take over Governorship himself, remain part of the Imperium and recompensate the Administratum for any disruption this is an internal political matter. Arbite has no authority.

This might depend on the specific situation the planet finds itself in. Civil wars are destabilising a world at least temporarily. If the noble is attempting to usurp governorship whilst the planet is in a time of crisis, perhaps exploiting the fact that the governor has just sent his armies to quell a mutant uprising, cultist influence, or an Ork invasion, then the rebellious noble's actions are treason against the Imperium itself, as they could hamper the planet's influence to defend itself. In such a case I could see the Arbites intervening on behalf of the governor simply to prevent a loss of life and war materiel that is critically required elsewhere. Likewise if the Arbites believe that this rebellious noble would be more trouble than he's worth (for example by not having sufficient influence on the populace) - they would become very much like a Praetorian Guard in this respect, except that they are protecting or making not an Emperor but the Emperor's hold over this world, as personified by a Governor sanctioned by decree of the High Lords.

That being said, ultimately I'm not even sure one should look too closely here. In the original source material, Imperial Law, especially as enforced by the Adeptus Arbites, has been said to become ridiculously complicated as a result of bureaucracy, so much so that the Arbites themselves cannot keep track of it. What's okay in one Precinct might be out of the question in another, and the only reason this doesn't cause more trouble than it does already is the limited interstellar mobility of Imperial citizens, Arbitrators included.

So perhaps it should depend more on how clever the Arbitrator's player is, and whether he manages to talk his way out of this mess.

Wow, thanks everyone. Really detailed stuff, I love it!

For the record, much to the chagrin of the rest of their party, the whole impersonating a noble thing was an attempt to grift the lesser populace of the hive. Although they didn't make all that much money before they were discovered.

If it comes to it, I would like to haul them before a judge and see how that plays out. Am I correct in assuming that the planet likely supports its own (probably quite corrupt) courts system that's separate from the Arbites courthouses?

For the record, much to the chagrin of the rest of their party, the whole impersonating a noble thing was an attempt to grift the lesser populace of the hive. Although they didn't make all that much money before they were discovered.

LOL!

Right...because the general population of the Imperium don't have enough misery without acolytes of the freakin Inquisition abusing their position.

I say the Inquisitor mind wipes the suckers and turns them into Servitors out of general principle.

If it comes to it, I would like to haul them before a judge and see how that plays out. Am I correct in assuming that the planet likely supports its own (probably quite corrupt) courts system that's separate from the Arbites courthouses?

That's a juridiction question. They were impersonating nobles, they may have a court, they killed enforcers, so depending on who's funding them they may have a court, but an Arbite was abusing his power, so the arbites may demand jurisdiction to save their own butt from the political backlash. The Inquisitor may just have his own court held with all three factions as prosecution vying for more drastic punishment.

Some may just seek out their own justice on them.

Wait wait wait... So the arbitor thinks that it is right to impersonate nobles to earn petty cash... As others have said, mind wipe and servitor for him! You can´t really defend theft like that.

In another note, I am curious now, how the heck does nobles get money out of the lesser populace? I mean... they get their money from the things they own, must work like profit factor in RT, so they can´t really knock on peoples does saying that they have to pay tithes to them. How the heck did they get people to give them money?

It was convoluted and I really have no idea where they were going with it, but essentially they built up this false noble through various means with the Arbiter acting as his Champion; to the point where this "noble"'s name had become known. At that point, they produced some dubious quality "holy relics" and sold them off using this noble's name for a very minor profit (like 30 Thrones total in all). It was all very minor and relatively under the radar so I really didn't give them much in-game resistance to their plotting.

However, the group as a whole inserted themselves into a rivalry between two noble houses and eventually angered some noble that had the ear of the local Magistratum office. And the rest I kind of explained before: After being taken in for questioning, a check was done on their backgrounds; indeed, this noble was no noble at all. Initially, they were just going to let the Arbiter go and keep this false noble, but he insisted on staying, He was then informed that in that case he would be charged as an accomplice to the crime. As they closed in to handcuff the pair, the Arbiter choose that moment to whip out his Arbites badge and a mighty speech about his authority, but a truly terrible fellowship role resulted in the enforcers slapping the badge out of his hands. Then came out the guns and the resulting bloodbath.

That sounds legitimately heretical in nature, they're not gonna have a fun day in court.

Well... so long as they had fun doing it...

I would personally just get a cleric and then do the same scheme if it was me. I mean... bend a fork a little bit and it will look like a two headed eagle. Why did none of them have any trade skills so they could be really heretical and make their own holy items?... And why the hell do I almost want to try doing some of the same things now. Shame on you! You are bad influence!

If it comes to it, I would like to haul them before a judge and see how that plays out. Am I correct in assuming that the planet likely supports its own (probably quite corrupt) courts system that's separate from the Arbites courthouses?

Technically, yes - there is Imperial law and there is local law. Both have their own judiciary and executive. An Arbites being tried and sentenced in a local court is kind of dubious, however. If this were in line with Imperial law, it would absolutely declaw the Arbites because any local Governor could "legally" have them arrested if he or she feels threatened. Rather, I would suggest bringing in the local Arbites Fortress-Precinct and a high-level Judge. Not only because such an approach preserves the Arbites' independence from local government, but also because a rogue Arbitrator is a serious offence to the Lex Imperialis itself and everything the Arbites stand for.

For inspiration, perhaps the story of fugitive Arbitrator "Bloodhound" Damian from GW's Inquisitor game could be of interest:

http://games-workshop.com/specialist/inquisitor/bestiario/damian.html

http://en.wikipedia.org/wiki/Robber_baron

At that point, they produced some dubious quality "holy relics" and sold them off using this noble's name for a very minor profit (like 30 Thrones total in all).

Hahah, if that comes out during the investigation, I can see the Ministorum wishing to have a word or two as well. If anyone is allowed to sell fake relics, it's them!

Although it does occur to me...why did the Arbite still have his guns on him if he had been hauled in for questioning by the enforcers?

I understood it as if they were about to bring him in - the Arbitrator just had different plans.

->

As they closed in to handcuff the pair, the Arbiter choose that moment to whip out his Arbites badge and a mighty speech about his authority, but a truly terrible fellowship role resulted in the enforcers slapping the badge out of his hands. Then came out the guns and the resulting bloodbath.

That's what I thought but re-reading the post I realised it seemed that the Acolytes were in custody but perhaps not under arrest at this point.

After being taken in for questioning, a check was done on their backgrounds; indeed, this noble was no noble at all. Initially, they were just going to let the Arbiter go and keep this false noble, but he insisted on staying, He was then informed that in that case he would be charged as an accomplice to the crime. As they closed in to handcuff the pair, the Arbiter choose that moment to whip out his Arbites badge and a mighty speech about his authority, but a truly terrible fellowship role resulted in the enforcers slapping the badge out of his hands. Then came out the guns and the resulting bloodbath.

In any case it seems like there has been a major screw up by pretty much every Imperial organisation. I would basically say burn fate points to avoid servitor mind wiping and have the PCs accept suspended sentences i.e once they have outlived their usefullness as acolytes they are going to be made into Servitors.

Whait let's count the crimes:

impersonating a Noble (Imperial Law, Nobles)

faking and selling relics (Ecclesiarchy)

faking documents (Imperial Law)

resisting arrest (local law)

killing officers/law enforcement (local law)

Wow, they pissed of 4 powerful factions, Arbites, local law, Nobles and the church. Their Inquisitor must be furious.

Tell me, did they do some Tech Heresy as well? Just to round out their portfolio.

While these groups debate who gets to burn them all will send their agents to catch them.

Sooner than later they'll be dead or in a holding cell.

If I were their Inquisitor or responsible superior agent i'd make them disappear and resurface as parts of (not for) several servitors.

Whait let's count the crimes:

impersonating a Noble (Imperial Law, Nobles)

faking and selling relics (Ecclesiarchy)

faking documents (Imperial Law)

resisting arrest (local law)

killing officers/law enforcement (local law)

Wow, they pissed of 4 powerful factions, Arbites, local law, Nobles and the church. Their Inquisitor must be furious.

Tell me, did they do some Tech Heresy as well? Just to round out their portfolio.

While these groups debate who gets to burn them all will send their agents to catch them.

Sooner than later they'll be dead or in a holding cell.

If I were their Inquisitor or responsible superior agent i'd make them disappear and resurface as parts of (not for) several servitors.

Well in fairness the noble faction might favour firing squad over burning.

If you don't want to completely bone them, this may be the oppertune moment to mention "Black Crusade"...

Again, thanks for all the ideas everyone. I'll keep this thread updated with what happens in the sessions ahead for those that are interested.

Some people mentioning their inquisitor's feelings about the whole thing. She currently is unaware of the situation as she is currently on a different planet perusing different leads. Most assuredly she is monitoring her acolytes in some way, but news probably won't reach her for some time.

There are always cell leaders you know, what are more humiliating than getting the lesson once... only to get it again when it goes to the next rank in the system, and again and again and...

Yeah ... the only way they aren't getting executed/turned into arcoflagellants is if they were attempting to establish a cover identity to go undercover/infiltrate a group of heretics/recidivists/etc in some fashion.

Do not suggest this to them. Find out exactly why and where they were going with the whole scheme. It has, of course, failed miserably, if it was part of a larger plan, but they might escape death/servitorization. They still, of course, need to complete their original tasks and investigations, which will be significantly more difficult now.

The Imperium is an unforgiving government, existing in an unforgiving universe.

As for monitoring them in-system, it could be an Interrogator, or a more senior Acolyte, rather than the Inquisitor herself. Someone with moderate independent authority of their own. Someone who will come in, smack them around and probably lock them up for a final decision to be made - it might not even reach the level of the Inquisitor, after all, a senior underling would likely have the authority to determine their utter incompetence and general lack of fitness for serving in His Majesty's Inquisition, and either terminate them or leave them hanging.

If they're claiming they're immune from prosecution because Arbites and Inquisition, it is rightly a matter for an Inquisitorial representative to evaluate the truth of - if they're the real deal, nobody really wants to risk drawing the ire of the Inquisition, but if they're imposters, the Inquisition is going to want to do terrible things to them. The locals are going to pass the buck to the actual Inquisition.