I'm going to be running a sinister and sly sociopathic Shardmind in my mate's upcoming EVIL campaign. It kills for much the same reasons that a real life sociopath turns to murder. His emotions are so muted that the massive emotional highs are the only one's she can experience. (It got into adventuring for much the same reasons.)

However I figure that the telepathic angle gives me a new option to explore the whole serial killer thing from. He doesn't just get his own rush from killing something. She shares the targets. (The targets emotions and sensations as they die. She doesn't loan a victim to another serial killer and share in the rush. At least not until after they've reached third base.)

As such it keeps the victim on her person in a bag of holding (Buffalo Bill style I suppose.) but in order to keep the air circulating she is going to have to hold the bag open for at least some time or just have them die of suffocation. (Which would be a fine way to kill the victim. If it weren't for the fact that they would fall unconscious before they die properly. So you lose something in the whole parasitic emotional link thing.)

In any case is there any way that I can magically gag or mute the person in the bag to keep them quiet? Just leaving the bag open is the best option but then they can shout and scream for help.

I figure that he could:
-Inject their voice box with a powerful but diluted paralytic. Deadening the organ and stopping them from talking. (Not a bad choice but it would require re-administration and that's inefficient.)

-Remove the voice box manually. (Probably the best option. It would weaken the victim and silence them at the same time but it would also be fairly fine work and Fornication only has an 8 for it's dexterity score and no training in healing.)

-(The same problems hold true with this next option.) Cut the spinal cord. (But there are a couple of new issues. This would make it difficult to torture the targets and give them an extremely short shelf life. It would however also allow her to carry several victims at once. Which increases the risk of getting caught when collecting a new batch.)

-Silencing them with some kind of magic item. (Third best choice. Unfortunately I can't find any kind of item that would do the trick. I could probably ask the DM for one that would do the trick but I would need one that would work on any sentient species and that could be hard to justify. [He's hardly picky.])

-Casting the Silence Ritual on the contents of the bag every morning. (Maybe second best option. It would probably work best in a non-urban area [that we're not going to be in] but casting the same poorly defined ritual on the same object every morning would raise suspicions and it lacks utility.)

Also:
Disposing of the bodies. Is there any way that I can stop Speak With Dead from working on a corpse if it's discovered? I suppose Fornication could just feed the bodies of the previous victims to the current ones but then he's got to keep them healthy and deal with the smell of the decaying bodies as well. (I've already got a method of dealing with the smell of the excrement that they're going to be producing.)