This was used in cases of murder where the suspect became their own witness. It involved a circle of Healers who sought the truth from the suspects own mind. Should the person resist than they were quick Tal-Shaya as a merciful form of execution though this only occured in cases where the suspect hide their shameful thoughts. Whilst Vulcan was noted for not experiencing any crime, the Verification was still considered a respectful law. According to the rules governing it, any injured party was allowed to attend it whether they were the healer or not.
The technique itself involved a group of healers who mind melded with the subject and forced them to open layer upon layer of their mind until they found the truth or falsity of their claim. This meant it was a difficult as well as dangerous procedure which typically only Vulcans were allowed to attend. Whilst others could possibly attend, this was typically the case with telepaths only as objectivity as a requirement during a Verification. Typically, an arbiter and guardian who was not a healer was also involved in the process in order to prevent it from straying into areas where the subjects privacy was breached as they were irrelevant to the investigation at hand.
In 2267, Sendet was facing Verification after a number of murders in the Vulcan Science Academy. This procedure determined that he was innocent but revealed that he was a member of the Followers of T'Vet. (TOS novel: The Vulcan Academy Murders)