The maintenance logs, of course, are there to be seen. Anna Hess duly reports the findings, which I didn't even have to tamper with to get the results I want.

Captain Forrest authorises me to investigate. He's clearly shocked and grieved at the thought that I may find a pleasant young man has been suborned by enemy forces. Both Hess and Rostov have spoken out in Roberts' defence, citing his thorough professionalism and spotless record, but as I pointed out, the enemies of the Empire are everywhere. We can't afford to let favouritism stand in the way of rooting them out.

I suspect Sergeant Mayweather is hoping to be summoned to help out with the interrogation, but I don't see why he should have all the fun. I appreciate watching him at work, of course, but he does very occasionally forget just how strong he is; Martin Roberts is not a very powerfully built chap, and I fear a couple of encounters with the good sergeant's fists would probably cave his ribs in – rather counter-productive when the aim is to make him talk.

Not that he's going to talk, of course. Primarily he's going to listen, and after studying his personnel file and investigating his background, I have some interesting things to talk to him about. Specifically, three interesting things – i.e. his mother and two sisters, and what may befall the immediate relatives of a man found guilty of High Treason.

His mother's not bad; I'd still give her one. As for his sisters, I'd have both of them at once. Not at all an unusual request when pretty little teenagers end up in a comfort house.

The obliging people at Headquarters have managed to find or produce images of all three of them that make it clear they're entirely acceptable material for expiating his sins. Really, I'd have thought somebody would have known better than to store a photograph like that third one online, even in a supposed 'secure vault'. It's not at all the sort of thing an affectionate brother needs to see, though I certainly don't mind having an ogle.

So far, the prisoner has steadfastly denied having neglected to check absolutely every joint and valve on his section of the coolant system. Yes, his electronic signature and thumbprint are on the logs, but he did his usual work and is convinced he did it up to his usual high standard.

Nice young man, he was, when he came on board. Soft, fairish hair, hazel eyes that tried to look resolute; a bit of what I'd describe as a Mort d'Arthur look. He'd have made a decent Tristan, or Lancelot even. I remember he squealed a bit, at first, and then he just gritted his teeth and stayed quiet.

I've sprayed on the aftershave I usually use for those initial 'inductions'. It's amazing how few people understand how effective smell can be in an interrogation; I only have to walk past him and he flinches away as if I've hit him.

Later, Roberts. Later. If necessary. Though I doubt it.

I sit on the other side of the table and watch him in absolute silence for about fifteen minutes. I don't move, I hardly blink. I just watch him, while the sweat oozes down his face and he tries to ease cramped muscles where the restraints are holding him to the chair.

Then I give the command to the computer to bring up the photographs on the shared screen on the wall.

His mother's first. A beach shot. Quite nice too, considering. Experience suggests it's probably a manipulation, but whoever did it was good; smoothed out any little imperfections in the flesh and didn't bother removing too much fabric from the swimsuit, just added a few details to provide a nice bit of titillation.

Then the older of the sisters. They're both blonde like Mum, but this one's on the short side. Photographed through what looks like a changing-room mirror, and charmingly unselfconscious in lacy bra and pants. Still, she fills out the bra very nicely. I can imagine customers definitely fancying a bit of those.

Followed by the youngest. Roberts gives a stifled sob and turns his head away. I give out a purr of appreciation and drop one hand under the table as if my trousers are suddenly tight and the contents need attention. Which I'm more than happy to provide in his peripheral vision, while I study this extremely frank photograph of Martin Roberts' little sister making her boyfriend a very happy man and apparently enjoying the experience immensely. Presumably he photographed her in flagrante delicto as a memento of the occasion. I'm entirely on his side; I'd shove it up that too, even if she is hardly old enough to give consent.

Deary me, that's not very nice language, Crewman. And I'll have you know my parents were married some years before my conception.

"Well, I can certainly see where the courts are going to go with this when you're sentenced," I remark, reluctantly stopping before I get carried away altogether.

"I'm not guilty, sir!" he almost screams. Not for the first time, and he's certainly not guilty of what he's being accused of but he's guilty of pissing me off over Cutler, and this is the payback. I'm merely surprised he hasn't realised yet.

"No?" I raise my brows at him. "So who do you think failed to deal with that fault on the valve? Father Christmas?"

"I did all of them!" He tugs desperately on the restraints. "I know I did! I've done them a thousand times, I never miss one of them!"

"Ah, but that's exactly where carelessness creeps in." I smile at him fondly. "When a procedure becomes a habit. Your brain can play tricks… your memory suggests you've done something when you actually haven't. And that's all it takes."

"It didn't! I swear, it didn't! I did them all!"

I cross my arms and look regretful. "Then unfortunately, Crewman, we're left short of an explanation why Commander Tucker is now in Sickbay with half his face scalded off."

He stares at me and then makes the mistake of looking at the screen, where the younger Miss Roberts is still a very happy and thoroughly jam-packed young woman. Needless to say, he doesn't look at it for long.

"I don't know!" he groans. "I swear, sir, I've no idea! I don't–"

"Well, that's very unfortunate," I shrug. "Ultimately, unless we happen to come across any alternative evidence that will stand up at court martial, I'm afraid you're the only suspect we have. And given that your name is the last on the maintenance log, and the access logs show no-one else entering the area, I'm afraid that evidence points very firmly in one direction."

"But I didn't do it! I didn't do anything! Sir, I swear, I didn't–"

There's a small but significant splash as the penny drops. He stares at me as if I've grown horns and a tail. "It was you, wasn't it?"

I'm good at expressions of outraged innocence. I've had to practise so often I could produce one in my sleep if I had to. "Making ridiculous accusations against a senior officer won't help your case, Crewman. The whole bridge crew will testify I was at my post there when the accident happened, and the access log proves I did not enter the area in question."

"The access log shows you didn't enter it," he shoots back bitterly. "Given the access you have as Head of Security, sir, are you honestly going to tell me you couldn't have got at it and cleared the evidence?"

This interview is, naturally, recorded.

"I probably could have done, if it was absolutely necessary and I was disloyal to the Empire," I reply smoothly. "But given the fact that I have no reason whatsoever to commit sabotage and endanger the Empire's flagship, I would be interested to know what reason you can imagine why I should do any such thing."

He opens his mouth to tell me exactly why I've framed him, and I gleam warning at him.

"Before you speak, Crewman, I should advise you that unfounded personal attacks will be treated with the contempt they deserve. Doctor Phlox has already entered notation in your record to the effect that you're suffering episodes of mild paranoia.

"I'm already aware that you suspect me of a completely unprofessional interest in Crewman Cutler, and I won't dignify such an absurd suspicion with a response."

I've whipped the ground from under his feet. He stares at me helplessly as I rise leisurely from the chair.

"You know, I can't help feeling that a few minutes' calm reflection might lead you to the decision that co-operation might be your best option. I've got a report to write, so I'll let you stretch your legs and visit the head." How extremely thoughtful of me, considering the young man must be nearly pissing himself with fear by now. "Then I suggest you sit down calmly and consider your options, Mister Roberts.

"Think very carefully. Because it's not just you who'll suffer unless you make the right decisions here." I cast a glance at the still full and happy Miss Roberts. "I suggest you bear that very much in mind."

I walk to the door. Before I open it, I press the button on my belt to open the restraints holding him in his chair, and turn to give him a measuring stare. "Think long and hard, crewman."

The pause should have brought his gaze around to me, and more specifically to the cupboard beside the door. Where the butt of a phase pistol is just peeking into view, sitting on the top – in a sea of dust, which will come in very handy to prove I didn't put it there on purpose. (Actually it's been there for ages, and very comforting it is too, knowing there's a weapon I can get hold of in an emergency; though it hardly needs saying that prisoners aren't normally released long enough to get hold of it, even if they notice it's there.)

I'll give him ten minutes. Then I'll take a peek in the monitor before I go back in. If he's found the pistol and decided to try something stupid, I'll just flood the room with something rather unpleasant that will knock him out eventually. Then, when Phlox brings him round and deals with whatever effect it had on his lungs, we'll start the proceedings again. Hopefully, however, he'll realise he's got as many actual options as a bullock in a crush waiting to be neutered.

There's a pallet of cases of valve sealant sitting in a recess in the corridor almost opposite, waiting to be transported somewhere. I pull a PADD out of my pocket and sit down on one, and start scrolling through the latest disciplinary reports; I don't want any accusation that I'm going soft.

It takes a bit longer than I thought it would. Honestly, if he'd taken my advice and used the head first…well, he'd still have thought about his options and reached the same conclusion, I suppose. The only question would be whether he'd have discovered the solution to his problems as quickly. I've left my communicator open, tuned to the audio feed from the room.

There are a few footsteps; he's spotted the pistol. Then a bit of a silence while he weighs his options and finds he hasn't got any – none that will save his mother and sisters from a comfort house as the family of a convicted traitor anyway.

Of course, if he hasn't been court-martialled he can't be convicted. If he hasn't been convicted he may be written off as the probable culprit, but I suppose we don't have to proceed against his family. Though next time I pay a visit to Earth I think I'll find the time to make a call to the Roberts house, all the same; I have a feeling I might enjoy meeting them. The enjoyment may not be mutual, but I can certainly duplicate the experience the younger Miss Roberts apparently found so delectable; with their mother strapped to a chair and a MACO standing with the muzzle of a phase rifle pressed between her eyes, I foresee that both of the Misses Roberts will discover an insatiable urge to make me happy. (I might even give the MACO permission to have a bit of fun while he's on guard duty. Let's be honest, he only needs one hand to hold a phase rifle, and I wouldn't mind him watching while I fuck her daughters.)

He thinks about it a bit longer. I've said he's not stupid.

Then there's the sizzle of a phase pistol discharging and the thump of a body hitting the floor.

Oh dear.

What a shame.

Nurse Cutler will be sorry.