There can be differences of interpretation and word usage that complicate describing phenomena like those in question here. This can obscure the true nature of some phenomena if one is not careful. When it comes to the actions of the interlopers, they are not soul-based beings to begin with. They do not believe in the soul and they do not do anything that is truly soul directed, at least intentionally. Much trauma they cause does affect the soul, and sometimes quite dramatically, but that is a distant interaction from the plane of the physical and will not be perceived by them. This is how they can be brutal without understanding the true depth of the injury they cause nor its consequences to them from a karmic backlash. So while technologically quite advanced, they are metaphysically primitive in their thinking and more literal than nuanced in their appreciation of the dynamics of energy when it comes to the broader meanings held by the divine realm. Being loveless, they completely miss the point of existence and the nature of interpersonal interactions in how they would be conducted in an ideal fashion at a divine level.
So what they do to manipulate people is done energetically and through psychological pressure or manipulation clandestinely, and often within the deep recesses of the mind that are inaccessible to the conscious awareness. So they can alter a person and manipulate them quite profoundly without the conscious self being aware this is happening, and then may find their own self changing over time in unexpected ways and go with the flow, not even realizing it is a manipulation being brought about because their thoughts are perceived to be their own and the feelings are perceived to be their own and, in fact, this may well be true from the inner origin of the programmed beliefs—the poison seeds have been planted and sprouted, and the person is simply harvesting the end product which will be a degradation in some fashion of their function.
So there are many types of manipulations, including suppression of the mind entirely, but this is not a soul manipulation, it is simply the manipulation of the extension of the soul present within the human body. That cannot be captured or controlled. It can be suppressed from conscious awareness and then portions of the mind forced to think certain ways and act certain ways and have the body carry out new wishes and desires generated through a kind of programming. So that is a manipulation only and a temporary distortion of the human in question. When they die, they will return to the light and realign with their soul and will not be altered permanently by what has taken place. It will be on record within the akashic record stores, and upon returning in a new incarnation, the individual will reconnect to the akashic records and the energies of the prior life experiences will reconnect to them and begin to influence all that happens.
So, in a sense, the journey back to the light is a timeout for rest and recuperation and will not heal the karmic wounds of the prior life in the physical. So the hazards are to be commandeered to suppress one’s own mind and have alternative programming instilled and reinforced to be focused on and expressed by the human being manipulated, or to manipulate them during their transition from the physical body at the moment of death to prevent their return to the light and to keep them earthbound and trapped in limbo as a kind of punishment and/or containment system that is, in effect, a prison to keep the person from coming back and being a troublemaker once again.
But there is no true soul capture. All that can be manipulated is the small expression of the soul that is present in physical form as you perceive it from your vantage point as physical human. The fears being generated here are, in essence, the awareness that one can lose oneself by abrogation of their sovereignty when the free will, free choice, free thought, in fact, are suppressed, and programming of all kinds can be substituted in their place. This certainly fits a loose description of having the soul taken, but that is more metaphor than reality. The functional state is, of course, not only undesirable, but likely devastating to the soul journey because there will likely be severe karmic consequences in addition to the harm from losing opportunities during the lifetime to do something truly desired, or that would be truly desired by a fully functioning and healthy person, and not someone who has been manipulated and distorted in their thinking.