decision include personal attitudes and the decision-making model where the officer works. Racial profiling can be systemic. The three types of primary sources that the Court accepts to determine suspiciousness are information obtained from third parties, information based on the suspect’s appearance and behavior, and the time and place of the suspected offense. Officers can define what they believe is normal, and if and how the suspect deviates from this. Reasonable suspicion has been used for actions like standing in the wrong place, nervousness, exceptional calmness, or walking quickly in another direction. Officers' experience may make them suspicious of behavior that is usually innocuous. For instance, a social interaction such as a hug or a handshake can be perceived as a drug deal. Suspecting people because they fit into a broad category, such as being in a particular location, being of a particular race or ethnicity, or fitting a profile, are insufficient for reasonable suspicion. However, stop-and-frisk has been validated on the basis of furtive movements; inappropriate attire; carrying objects such as a television or a pillowcase (in English law, "going equipped"); vague, nonspecific answers to routine questions; refusal to identify oneself; and appearing to be out of place. Before 1968, the law required substantial evidence to impede liberty or seize property. But the Fourth Amendment does not protect consensual encounters. During the Terry case, the Supreme Court found that the police should have the power to search, even without probable cause, to protect themselves from weapons. The Terry stop operates under the assumption that though stop and frisk is an intrusion, the potential harm from weapons outweighs it. The cases following Terry expanded the power of the police. While the original case was concerned with armed violence and firsthand observation by officers, Adams v. Williams (1972) extended the doctrine to drug possession backed up by the secondhand hearsay of an informant. The Adams v. Williams case set a precedent in that police did not need a first person observation but could get information from a confidential informant instead. Regarding this case, Justice Marshall stated, "Today's decision invokes the specter of a society in which innocent citizens may be stopped, searched, and arrested at the whim of police officers who have only the slightest suspicion of improper conduct." United States v. Hensley (1985) ruled that police officers may stop and question suspects when they believe they recognize them from "wanted"