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Debunking Myths Regarding Source Information

Is it true that “tips” from concerned citizens, confidential informants and anonymous callers can establish reasonable suspicion or probable cause? This is the fifth in a series of articles that identify and debunk some of the greatest myths in police law. These common misunderstandings are a result of many factors, not least of which is inconsistency among our own trainers, prosecutors and judges.

It is important, though, for supervisors and managers to accurately distinguish between common misunderstandings and correct law so that they apply correct standards in their assessments of officers. Officers need to make the same distinction so they are able to properly apply the law.

Naturally, our training should reflect the law as it is—not as it might be pervasively misunderstood. Each agency should decide on and announce its philosophy toward prosecutorial and judicial agendas that may be different (often more restrictive of police behavior) than the law actually is.

Consider the Source

An ordinary concerned citizen waves down a patrol officer to report a person selling drugs nearby. A confidential informant requests a secret meeting with an investigator to show him where stolen property is being stored. An unknown caller identifies a robber who was shown on the news but doesn’t want to leave her own name. Each of these situations will lead to information for the police to consider, but do they provide sufficient information to establish reasonable suspicion or probable cause? When can the police act on the information they receive from these sources?

Police receive information from a variety of sources; inevitably, some sources will be more credible than others. When determining whether reasonable suspicion or probable cause exists, it is the police officer’s responsibility to “consider the source” of the information, as well as the value of the information that the source provides. All of them can be trusted a little, but none of them can be trusted completely.

Concerned Citizens

Lacking a reason not

to believe the ordinary concerned citizen, police may generally presume that a citizen who reports information to the police is credible. Law enforcement should encourage citizens to provide information whenever they have knowledge that may be useful in identifying and fighting crime. When a citizen flags down a police officer and provides information about criminal behavior, the police should listen. An apparently truthful citizen can provide reasonable suspicion, and potentially even probable cause, to stop a suspect.

Police should not ignore obvious biases or reasons that the citizen may have to lie, nor should they discount a citizen’s information because of a speculative possibility that they “might be lying.” So, for purposes of developing reasonable suspicion and probable cause, officers may presume that the citizen is being truthful, unless there is reason to think otherwise.

Police officers should be wary of information that is provided by citizens when the information is not within the citizen’s own knowledge, such as when a person reports what a neighbor or a friend told them. It is reasonable for the officer to believe that the reporting person is telling the truth, that their friend did in fact tell them these things, but it is well known that as more people relay the story, the less accurate the details become. Officers should not completely discount this kind of second-hand information; they should simply recognize its reduced value and consider the credibility of both links in the information chain.

Other Officers

Law enforcement officers frequently share information about suspects and criminal activity, and it is reasonable for the police to expect that other police officers are being truthful when they provide this information. The same concept applies to communications from other law enforcement agencies. They are deemed reliable unless there is some reason to doubt their accuracy.
Therefore, when police officers receive information regarding active warrants, suspect descriptions or criminal activity from other officers or agencies, even through their communications center, they can rely on it to establish reasonable suspicion or probable cause in their own investigations. There is no need to verify what is conveyed to them from other officers or from other law enforcement agencies; their statements are presumed to be true.

Criminal Informants

Informants who are themselves involved in criminal activity are a different matter. They have both reason to lie to the police and reason to tell the truth, so the things they tell the police need to be verified or there must be some other reason to believe them. Criminal informants may lie to curry favor with investigators, or they may fabricate information about a rival to distract the police from their own misconduct.

On the other hand, criminal informants have valuable insight into the details of criminal activity because they are personally involved. So, their status as criminals simultaneously diminishes and enhances their credibility. Police officers have to balance these competing factors and bolster the believability of these witnesses before they can rely on their information for legal purposes.

Several options are available to police officers who need to establish that a criminal informant is trustworthy. One method is to build a “track record” of this person providing truthful information. If an informant (criminal or not) has previously given reliable information to law enforcement, it provides some basis for believing that his current information is likewise reliable. A history of candid interactions with an informant is even more valuable if the relationship is maintained over time and if the information has lead to other arrests, seizures or even convictions.

Another way to increase a criminal informant’s standing is to pay for the information that he provides. Payment provides some incentive for him to be truthful, especially if he may be paid again in future dealings, but it may also encourage him to provide false information merely to collect the payment. Officers should be careful not to pay for misleading or false information, and they should not pay such an amount that it would encourage criminal informants to lie for the money.

Corroborating an informant’s statement (verifying some of the information provided) is another way to enhance his credibility. If law enforcement is able to show that a substantial part of what the informant told them was in fact true, then it is reasonable to believe that the rest of what this person told is also true. The extent to which a criminal informant’s reliability needs to be demonstrated varies with each situation. It is a matter of deciding when it is reasonable for the police to believe what this known criminal is telling them.

Confidential Informants

A confidential informant is a person who provides information to the police and whose identity is held in confidence throughout the investigation. Confidential informants usually want their names withheld because they fear repercussions for revealing information about dangerous people. That alone should not cast doubt on their honesty; however, a confidential informant could be a known criminal, which would make his credibility an issue after all.

The status of the confidential informant determines whether bolstering of his credibility is necessary. As previously described, if the confidential informant is an ordinary concerned citizen, corroboration is not necessarily required; if he is a known criminal, corroboration or a track record of reliability is needed.

Confidential informants, whether criminal or not, can provide reasonable suspicion or probable cause for law enforcement investigations once the requisite level of credibility is established. If a confidential informant has personal knowledge of where to find stolen property, he may be able to provide probable cause for a search warrant.

The substance of an informant’s contributions and the reasons for not revealing his identity should be thoroughly documented. If the case goes to trial and the confidential informant is a necessary witness, then the court will likely require the prosecutor to divulge the identity of this informant; if that is imprudent, the prosecutor may ultimately need to dismiss the case.

Anonymous Informants

A person who gives information to the police, but who is not identified (even by the police) is an anonymous informant. An anonymous informant’s credibility is dubious and needs corroboration before law enforcement can rely on their information for the purpose of establishing reasonable suspicion or probable cause. Anonymous callers may be involved in the criminal activity that they are reporting, or they may be innocent observers.

If the caller is at least willing to state how she knows the information, such as identifying herself as a neighbor or a relative, that will make her somewhat more believable than a caller who refuses to provide any identifying information whatsoever. Some courts may treat her as a confidential informant rather than an anonymous one.

Similarly, a repeat caller may establish a track record with law enforcement, even if the caller’s true identity is unknown. If the caller can be identified by other means, such as a CrimeStoppers number or a nickname they have provided, law enforcement may distinguish this otherwise anonymous caller as someone who has previously provided reliable information.

The key to making use of an anonymous informant is substantial corroboration. While police are obliged to investigate an anonymous caller’s allegations, they are not permitted to rely on them as accurate information until they have verified significant details provided by the caller. The Supreme Court has made a distinction between anonymous callers who provide insightful details and callers who provide rather generic information.

The Court found that an anonymous caller provided the basis for reasonable suspicion to stop a vehicle by providing detailed descriptions of the suspect and her vehicle and correctly predicting the timing and direction of the suspect’s movements (see Alabama v. White

, 426 U.S.325 (2000)). However, the Court also found that a caller’s information has failed to amount to reasonable suspicion when the caller merely provided a physical description of subjects who were in public view and alleged (although accurately) that one of the subjects possessed a gun (see Florida v. J.L

., 529 U.S. 266 (2000)).

Anonymous informants can provide the basis for a lawful frisk, stop or even arrest, but law enforcement must be vigilant in its collection and corroboration of details from such sources before relying on their information in investigations.

Consider the Credibility

Police can rely on information from various sources to establish reasonable suspicion and probable cause, but they must consider the credibility of their sources. Informants are attributed with different levels of credibility based on a logical assessment of what is known about them and their motivations to be truthful or deceitful.

Information that comes from other officers or concerned citizens is generally deemed credible; thus, law enforcement can usually rely on it for purposes of developing reasonable suspicion and probable cause. Informants who wish to keep their identities confidential are also generally credible, unless they are also criminal informants, in which case their credibility must be established. Information that is relayed to the police as second-hand information, as opposed to the informant’s personal knowledge, can be an appropriate basis for police actions, but the credibility of the original source must be established.

Anonymous informants require the most corroboration before their information can be relied on as a basis for police action. It is reasonable for the police to believe what they are told by some people. However, when those people refuse to identify themselves, it is unreasonable for police to conduct traffic stops or searches based on their information without first verifying some of the details provided. Where those details are nothing more than the description of a person already in public, they are less meaningful in establishing source credibility.

Randy Means is a partner in the Charlotte, NC law firm of Thomas and Means, LLP, and specializes entirely in police operations and administration. He is the primary legal instructor for the IACP. He can be reached at In her 20-year career, Pam McDonald has worked as a patrol officer, a felony prosecutor and a college professor specializing in police issues. She is currently assisting Randy Means. She can be reached at

Published in Law and Order, Dec 2009

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