Can Police Act on an Anonymous Tip?

Posted by Neil Shouse | Jun 24, 2019 | 0 Comments

a person whispering into another's ear

Yes. Police can act on anonymous tips if they follow the rules, laws, and procedures that have developed in accordance with the U.S. Constitution.

Police contact with people usually occurs:

  • on public streets,
  • in motor vehicles,
  • in homes or other buildings.

The Fourth Amendment of the United States Constitution guarantees:

The right of the people to be secure in their persons and houses against unreasonable searches and seizures, and no Warrants shall issue, but upon probable cause, particularly describing the place to be searched, and the persons or things to be seized.

A police officer may, in appropriate circumstances, approach a person for purposes of investigating possibly criminal behavior.

An investigative detention without a warrant must be based on a reasonable suspicion that:

  1. Some activity out of the ordinary has taken place;
  2. The activity is related to crime; and
  3. The person detained is involved in the activity.

The justification for the stop or detention by police must include:

  • Specific and articulable facts which support the police intrusion,
  • Based upon the totality of the circumstances.

If police are acting on an anonymous tip, courts will consider whether:

  • Police have confirmed or verified the information,
  • If the information is specific and/or reliable,

For example: Did the tip include the make, model, and license plate of a suspect's vehicle?

If police exceed their authority in stopping, detaining or arresting:

  • Evidence can be suppressed or thrown out, and
  • a criminal case could be dismissed.

Can police detain a person based on an anonymous tip?

A tip from an anonymous source may provide reasonable cause to detain a person if it includes some facts that are verified by police. Alabama v. White (1990) 496 U.S. 325.

A detention must be based on a reasonable suspicion that:

  • some activity out of the ordinary has taken place;
  • the activity was related to crime; and
  • the person detained was involved in the activity.

A search made during an investigative detention is illegal if:

  • there was no basis for an officer to believe the person was armed and dangerous;
  • the scope of the search was beyond a pat-down for weapons; or
  • the search extended to the person's possessions or vehicle, except that an officer may order a detainee to produce identification.

A real-life example is:

Two separate people approach police on a crowded New Year's Eve street and tell them a man in a white cap has a gun. The police can see only one man in the crowd with a white cap. They approach the man, pat him down, and find a gun. The court ruled the encounter was justified. People v. Coulombe (2000) 86 Cal. App. 4th 52.

Can Police Stop A Car Based on an Anonymous Tip?

Police must have probable cause or reasonable suspicion of criminal activity to stop a motor vehicle. Sometimes an anonymous tip can be sufficient.

The justification for the stop or detention by police must include:

  • specific and articulable facts which support the intrusion,
  • based upon the totality of the circumstances.

Courts will look at the source of the information that police are relying on:

  • is it confirmed or verified by police?
  • is it reliable?

For example:

An anonymous 911 caller told police that a truck had run her off the road. The caller provided the vehicle description and license plate number. Officers quickly located and stopped the truck. The officers smelled marijuana, searched the vehicle and found 30 pounds of the drug. The court ruled that based upon the totality of the circumstances, the officers had reasonable suspicion to think the driver might be intoxicated and could stop the vehicle to confirm. Navarette v. California (2014) 572 U.S. 393

An investigative detention is illegal if it is based on only one insufficient factor, such as:

  • curiosity, rumor, or hunch;
  • race or sex of the suspect;
  • suspect's presence in a high-crime area; or
  • a person's nervous behavior.

Can police search a house based on an anonymous tip?

Police must obtain a warrant to search a house. An anonymous tip, standing alone, does not provide the necessary probable cause for the issuance of a warrant.

The affidavit for a search warrant must include:

  • sufficient information to conclude that the informant is honest, and/or
  • facts indicating that the information is reliable along with the basis of the informer's knowledge.

The anonymous informant must actually witness the alleged criminal activity.

For example:

A tip by an anonymous informant that there was heavy foot traffic at a person's residence, by itself, is not sufficient to establish probable cause. Bailey v. Superior Court (1992) 11 Cal. App. 4th 1107.

Please note there are exceptions to the search warrant requirement for a house or vehicle:

  • exigent circumstances,
  • search incident to a lawful arrest,
  • consent,
  • plain view,
  • caretaker function,
  • motor vehicle exception,
  • vehicle inventory.

Please note that in any criminal case involving anonymous tips, arrests, or searches, it is VITAL to consult with an experienced criminal defense attorney.

If police exceed their authority:

  • evidence can be suppressed or thrown out, and
  • a criminal case could be dismissed.

About the Author

Neil Shouse

A former Los Angeles prosecutor, attorney Neil Shouse graduated with honors from UC Berkeley and Harvard Law School (and completed additional graduate studies at MIT). He has been featured on CNN, Good Morning America, Dr Phil, Court TV, The Today Show and Court TV. Mr Shouse has been recognized by the National Trial Lawyers as one of the Top 100 Criminal and Top 100 Civil Attorneys.


There are no comments for this post. Be the first and Add your Comment below.

Leave a Comment

Comments have been disabled.

Free attorney consultations...

The attorneys at Shouse Law Group bring more than 100 years collective experience fighting for individuals. We're ready to fight for you. Call us 24 hours a day, 365 days a year at 855-LAW-FIRM for a free case evaluation.

Regain peace of mind...

Shouse Law Defense Group has multiple locations throughout California. Click Office Locations to find out which office is right for you.

Office Locations

Shouse Law Group has multiple locations all across California, Nevada, and Colorado. Click Office Locations to find out which office is right for you.

Call us 24/7 (855) 396-0370