There are various synonyms that can be used for the phrase "made the subject of an investigation." These include being targeted, scrutinized, probed, examined, surveyed, reviewed, evaluated, analyzed, studied, and researched. All of these terms are commonly used to describe a situation in which someone or something is being investigated. They all imply that there is a level of suspicion or concern surrounding the subject in question. Whether the investigation is being carried out by law enforcement, regulatory agencies, or private investigators, these words are useful in describing the process and the subject's role in it.