Suspects and witnesses often reveal more than they intend through their choices of words. Here are ways to detect possible deception in written and oral statements.
The manager of a fast food restaurant calls the police late at night to report that an armed robber had entered the restaurant while the manager was alone in the office finishing some paperwork. The manager said the gunman had stolen the entire day's cash receipts — a little more than $4,000. The manager had reported a similar robbery at the restaurant about six months earlier. No other witnesses were present at either alleged robbery. The restaurant owner learns from police investigators that armed robbery is extremely unusual in the surrounding neighborhood. Also, the owner knows that the manager's wages have been garnished for the last year for nonpayment of child support. The owner hires you, a CFE, to investigate whether the manager is filing false police reports to cover his thefts. You begin your investigation by asking the manager to write a description of the evening's events.
Linguistic text analysis involves studying the language, grammar and syntax a subject uses to describe an event to detect any anomalies. Experienced investigators are accustomed to studying interview subjects' nonverbal behavior, such as eye contact and hand movement. Text analysis, on the other hand, considers only the subject's verbal behavior. Because text analysis evaluates only the subject's words, investigators can apply it to written as well as oral statements. In fact, many investigators prefer to analyze suspects' written statements for signs of deception before conducting face-to-face interviews.
Text analysis is based on research originating in the 1970s. Psychologists and linguists studied the language and word choices of subjects in controlled experiments and found predictable differences between truthful and deceptive statements. Susan Adams, an instructor who taught text analysis (which she called statement analysis) at the FBI Academy for many years, described it as a two-part process ("Statement Analysis: What Do Suspects' Words Really Reveal?" FBI Law Enforcement Journal, October 1996). First, investigators determine what is typical of a truthful statement. Secondly, they look for deviations from the norm.
The link below describes deviations that suggest a subject may be withholding, altering or fabricating information.