The technology behind targeting individuals appears to be caused generally by radiowaves. These radiowaves all exist within the range of what is non-ionizing (non-visible spectrum) radiation, which would begin with Far-infrared. While possible, many describe ranges of 1hz-299Khz as ranges to manipulate a human beings physical organs, though most existing  documentation does not provide any proof. Directed Energy Weapons have not been documented to work in such a range which usually ranges between 95Ghz-350Ghz (Extremely High Frequency Range). Very suspiciously,  the range of EHF (95Ghz-300Ghz) is almost entirely used by and only purposes are known by government agencies. The main component of DEW weapons is a device called a Gyrotron. A gyrotron is a class of high-power linear-beam vacuum tubes which generates millimeter-wave electromagnetic waves by the cyclotron resonance of electrons in a strong magnetic field. Output frequencies range from about 20 to 527 GHzcovering wavelengths from microwave to the edge of the terahertz gap. Typical output powers range from tens of kilowatts to 1–2 megawatts. Gyrotrons can be designed for pulsed or continuous operation. This component allows a Directed energy weapon to create a wavelength in the EHF range. Frighteningly enough, the damage from EHR ranges cannot be easily prevented or blocked even using a Faraday Cage (though technically possible), which has been determined by Japanese scientist to cause birth defects and many other issues.

Not much is known about satellites that operate in these frequencies, which have been launched as satellite payloads by the United States Air Force AEHF (Advanced Extremely High Frequency) program and private defense corporations such as Lockheed Martin. From the description, these payloads would not be easy to decrypt or understand, and would also require powerful and large Antennas to receive data from (which of course the Federal Communications would not allow for civillian use).

The technology used to target individuals was most likely created at the Air Force Research Laboratory(AFRL).

The following reasons are why this conclusion has been reached:
1) The AFRL is not only who builds warfare based satellites, but are the ones who setup the launches of secret payloads.
2) The AFRL created a microwave technology that can only be heard by a specific individual. DARPA who actively collaborates with AFRL also has worked on a project that emits a laser-transduced voice into a specific area.
3) The AFRL has been the main creator of various Directed Energy Weapons(DEW) in collaboration with the defense contractors Raytheon and BAE Systems. These weapons are mostly Active Denial Systems that fit the criteria of sensations and symptoms felt by Targeted Individuals. They also have built satellites integrated with DEW.
4) The level of secrecy of these programs is possibly the highest of the government and most likely require Q Clearance. This explains why the FBI and other agencies seem to have no knowledge of such programs and are very skeptical that they exist. The FBI and other agencies would never suspect or possibly even question a special military group. It’s likely that most agents are ordered to never question or suspect any military operation is violating the laws of the United States. Law enforcement of the military is conducted by the military via military law enforcement groups.
5) The AFRL specifically builds experimental military technologies. It is unknown of how these technologies are tested and upon whom the testing is conducted on.
6) The Air Force is mostly the only known users and creators of technologies around the wavelengths above 95Ghz. 95Ghz is the known frequency of many Directed Energy Weapons, especially Active Denial System. The small exception is researchers of plasma devices, astronomy, and radiography. At a certain level of wavelengths, the Air Force is the only users of technologies, especially in the higher ends of the SHF (Super High Frequency) and EHF (Extremely High Frequency) ranges. The technology at those ranges are completely unknown from a civilian perspective.
7) DARPA has for many years worked on and advanced Brain-Machine Interfacing technologies. These have been proven to be able to read the words and thoughts inside a human being’s mind. Many articles on this website provide substantial evidence of this.

LRAD (Long-Range Acoustic Device) has a 1Khz-5Khz range and is used as an ultrasonic acoustic weapon. These acoustic weapons can not only direct voices at a human being, but can also cause a burning sensation when directed upon human body tissue and organs. GPS (Geographical Positioning System) falls into the  range of SHF(Super High Frequency) with satellites running at 1.57542 GHz (L1 signal) and1.2276 GHz (L2 signal), which can precisely track a human beings movement, such that Targeted Individuals describe would be tracking their precise movements, even within a corridor such as a building or house.

An additional component to these EHF satellites and waves is Brain-Machine-Interfaces attached the satellites, which could possibly use fMRI (Functional magnetic resonance imaging) transceivers. fMRI has been proven to read the human beings mind, long term memory, and present thoughts (short-term memory). Many documented scientific proof of fMRI being used for these uses are on this website and are searchable, some which can read your exact current worded thoughts, long-term memory, or even a song you are currently listening to. Using transceivers, these devices could not only receive your thoughts, long-term memory, but even transmit thoughts via brainwaves that convert to hearable waves inside only the brain, and thus would not be a sound wave or audible to other people nearby. It’s very possible these transducers could speak to you via a technique similar to the Frey Effect (though it would project words via brainwaves) as well as induce a sleep like state via beta waves (which many targeted individuals have experienced and do exist in the hertz range).

It might be possible to obtain proof of these waves via an expensive Spectrum Analysis tool, which would could prove use of EHF or other waves being around an individual. A targeted individual could be surrounded by a range of waves outside of Faraday Cage, but many would be challenging or impossible to decrypt. If these waves were detected within a thin Faraday cage, with all electronic devices being turned off in quite a long range, this would provide definitive proof. Another way to prove targeting would be using a device such as a EEG or MRI. These devices would not only prove an unusual change of brainwaves from a clinical sense, but would also prove that the bio-markers for mental disorders such as schizophrenia are not biologically present. An MRI could prove that gray matter changes/damage like what was seen in the biological evidence discovered from the Cuban and Chinese sonic weapon attacks on US diplomats. Many scientist who study radiowaves would say that such use only appears in science fiction, but are possibly naive to the idea that many government agencies operate on black budgets (such as the CIA, which in 2016 had a $44 Billion dollar budget, which doesn’t even consider it’s absurdly large co-current budget since it’s inception as an agency.)

Though the phrase voice-to-skull (v2k) is frequently used in the Targeted Individuals community, though it appears that the technology behind v2k is actually an ultrasonic wave from a laser transduced wave, which makes it possible for only one person to hear v2k voices in “one’s head”. It seems though that the v2k moves the eardrum and thus is actually transmitted to ones ear and not directly to their brain, as others have asserted. Specific types of microphones safely inserted into the ear might provide proof of v2k.

One key component of evidence that voice-to-skull originates in the United States is how the perps who are speaking or typing through a command line program via text-to-speech (three agents/soldiers working 8 hours a day, thus 24/7 voice-to-skull) speak perfect and unbroken English. This means that they must be located in the USA and are most likely involved in a covert military operation.