PC comissar went insane. First he made a deal with stealthy "mercenaries", as they introduced themselves through comm devices. He gave them two "porters" that they requested for leaving the mission area without a fight. Those "porters" were regiment's prisoners. Throughout the session PC's were given many hints that those "mercenaries" eat ork meat and less probably - human.

He made that deal with blessing of regiment commander, but after those revelations he became suspicious about his new "friends". He didn't consult HQ though. Despite his fears he struck the deal.

Then player went meta: he assumed they have to be xenos, knowing stealth proficiency and eating habits of the kroot race. He called the HQ informing that "Deal with a group consisting probably of man-eating xenos was made. Mission successful". There wasn't a direct link to the HQ - he passed that raport to one of the outposts and the outpost passed it to HQ.

So now all the regiment "knows" that their comissar strikes deals with xeno man-eaters, probably with a blessing of regiment's HQ.

My question is: what should happen now?

Being regiment's commander I'd blame comissar entirely for not updating on mission status after learning that those "mercenaries" might be of xeno origin and carnivore. And also - being not too secretive about his mission. What should the punishment be? Imprisonment? Death?

Besides, whole regiment should start to hate that com. Xeno-loving comissar? That's just insane! That's what everyone would be talking about. So probably huge penalties to socializing with his own regiment.

Um .... The Commissariat is going to come down like the Hammer of the God-Emperor. Guard Higher is also not going to be happy with the situation. The PC Commissar is screwed . Regiment command is going to be investigated as well.

The Guard has no authority over the Commissariat - so all that Regimental Command can do is pray that the imminent investigation clears them of knowingly making a deal with xenos and pins the blame firmly on the PC Commissar and anyone who was with him, and pray that until then that none of the witnesses that could clear them of knowing/active involvement get themselves dead.

When the investigation happens, the Commissar is likely to be executed or worse, everyone who was with him is liable to be executed as well. The rest of the Regiment might also be up disciplinary actions as well.

The aftermath of the investigation should have the entire party rolling up new characters, all of whom are probably from a different regiment as well.

I know how I'm gonna play this. By coincidence, Lord Commissar stationed with the regiment is away on a mission. After our next session he'll be back with couple squads of storm troopers to arrest PC comissar. One other player won't be playing with us for a long time, so his character is going to be "recomissioned" to another regiment, as well as other pc, abandoned by other player. I think whether it would be interesting to play some kind of a trial. I guess not, because there's only one outcome possible - capital punishment. But the execution might be fun. The campaign started with the same comissar pc execution some cowards and traitors for the glory of the Imperium. Life of this character will end in the same way.

If he's lucky, the Commissariat executes him before the Inquisition gets their hands on him. And if the rest of the party (and regiment) is lucky, the Commissariat handles things and closes the investigation, trial, and carries out the sentencing before the Inquisition can grab them all.