Police can and do use anonymous tips to arrest people for criminal activity, and the Supreme Court showed support for this behavior via rulings on several relevant cases. While it's acceptable for cops to make arrests based on information from secret sources, that doesn't automatically make those arrests valid or any evidence obtained as a result admissible in court. Here are three ways to challenge the use of anonymous tips in your case that may result in a positive outcome for you.
Dispute the Source's Reliability and Credibility
Although the courts have made it easier for cops to use anonymous tips, those tips must still come from reliable sources and/or be credible in some way to justify using them. In general, an anonymous tip from an unknown or random source must provide adequate details about the crime in question.
In the case of Navarette v. California, for example, a citizen called 911 to report a truck driving erratically. The cops subsequently pulled the truck over and ended up arresting the driver for marijuana possession. The defendant disputed whether the cops had a valid reason to stop him since they didn't witness the act themselves, but the Supreme Court ruled the anonymous tip contained enough valid information (e.g. an eyewitness account, license plate number) to justify the police pulling him over.
Attacking the reliability and credibility of the anonymous tip is one way to get it invalidated by the court. You can call the witnesses honesty into question if the name of the tip supplier was revealed, or you can argue there was not enough specific information supplied to accurately identify you as the person who committed the crime. Your attorney can help you create the best strategy for discrediting an anonymous tip this way.
Argue the Tip Wasn't Corroborated by Cops
Depending on where you live, the law may require cops to verify some or all the information provided in an anonymous tip. If someone calls 911 claiming you were driving under the influence of drugs or alcohol, the police have to observe some telltale signs of a DUI in progress before they can detain you, for instance.
Using this tactic can be tricky because not all the details provided have to be corroborated by the cops or even correct. In Alabama v. White, an anonymous caller told police a woman driving a specific type of car would be dropping off cocaine in a brown briefcase at a motel. When the cops arrived at the suspect's residence, they saw the woman get in the vehicle described by the tipster and go to the specified motel. The problem was she didn't appear to have any cocaine. Even though not all the details turned out to be true, however, the courts found that enough of the tip had been verified to justify the stop.
Pointing out the lack of validation works best in cases where it's apparent the cops were relying wholly on the anonymous tip to make the stop; otherwise, you'll also have to attack the reliability of what the cops witnessed, which can be hard to do.
Deny the Tips Indicated a Crime Taking Place
Another way to challenge an anonymous tip is to show the information provided to the cops didn't indicate a crime was actually taking place. For example, someone calls in an anonymous tip that you were standing outside a building carrying a gun. You could argue the tip shouldn't be used if you live in a state where gun ownership and conceal/carry is legal.
Prevailing with this tactic will often come down to dissecting what the tipster said when he or she made the report and showing the court that no crime was actually reported to the police.
There are other tactics you can use to dispute the validity of anonymous tips used in your case. Consult with a criminal defense attorney from a place like Johnson Motinger Greenwood Law Firm for help with your case.