What actually happens to those taken away by The Lurking Fear?

Question

In H. P. Lovecraft's The Lurking Fear, the eponymous fear is noted for often not leaving any trace of its victims.

George Bennett and William Tobey had left no trace, not even of a struggle. They were never heard of again.

and

When we asked them to help us find Bennett and Tobey they were truly distressed; for they wanted to help us, yet knew that these victims had gone as wholly out of the world as their own missing people. That great numbers of them had actually been killed and removed, just as the wild animals had long been exterminated, we were of course thoroughly convinced; and we waited apprehensively for further tragedies to occur.

However, some victims, notably

Arthur Munroe

leave physical remains.

When I was first reading the story, I attributed the disappearance of victims to some sort of otherworldly influence, as if people were being literally taken elsewhere, but that seems unlikely when it is revealed that the "fear" is

The genetically and culturally degraded descendants of the Martense family, mutated or de-evolved into something not quite human, but still very physical and earthly, not gods or elder things.

Did I miss something in the story? Is the "disappearance" of many of the victims simply a testament to a particularly gruesome kind of murder that leaves little trace, or are the victims actually taken to some other location for some specific purpose?

I had a theory that

"Disappeared" victims are kidnapped for breeding stock. This makes some sense as it is mentioned in the story that the Martense family at one point was openly interbreeding with the "squatter" population, and after their final withdraw from society would have had recourse only to inbreeding unless they could regain a supply of outside genetic material. Perhaps the kidnappers found it impractical to take Munroe due to his presence in the cabin with the narrator, or perhaps they decided he was not a good genetic match.

but this seems not at all obvious and also not very Lovecraftian.

Answer 1

In many cases, there is plenty of carnage left behind by the man-eating Mertenses. The ghastly event that brings the protagonist and other investigators to the area involves plenty of gore:

The disordered earth was covered with blood and human debris bespeaking too vividly the ravages of daemon teeth and talons; yet no visible trail led away from the carnage.

The dramatic point about people being carried away is that there is no evidence of where the victims have been taken, or which way the perpetrator(s) have gone ("no visible trail" in the above quote). This is not supposed to be an indication that the victims are left alive; it is just there as a mysterious element foreshadowing of the fact that monsters travel around almost entirely underground—something which the protagonist does not figure out until late in the story.

Answer 2

The opening of the story indicates, to me at least that actually many of the victims, or at least pieces of them are found at the site where they are attacked. Of the lurker(s) it is said:

either carrying them off or leaving them in a frightful state of gnawed dismemberment.

And fully half the bodies of the village destroyed that prompts the narrators investigation were still present.

It's the word "gnawed" that gives the answer to me, the Martenses simple eat whoever they take. The Martense family legend indicates that they inbreed as a matter of preference. The lurkers are exceptional stealth hunters and can take victims or eat them on site as circumstances and preference dictate; Monroe's remains are probably left due to the proximity of the narrator disturbing the hunter(s) at it's meal.