When Can Police Use a Drug Sniffing Dog?

When Can Police Use a Drug Sniffing Dog?

Dogs have powerful noses. According to researchers at Florida State University, they can smell up to 100,000 times better than humans. Considering how amazing a dog’s sense of smell is, it’s probably no wonder why police use dogs to detect illegal substances. But what does the law say about drug sniffing dogs? Can police use a drug sniffing dog whenever they feel like it? What are your rights when it comes to traffic stops and contraband dogs?

The drug defense attorneys in Dallas at the Broden & Mickelsen, LLP take a look at what you need to know if you’re charged with a drug crime in Texas as the result of a drug sniffing dog.

What the Supreme Court Says About Drug Sniffing Dogs

The Supreme Court handed down a ruling about drug sniffing dogs in 2005 in Illinois v. Caballes. In that case, the Court ruled 6-2 that the police aren’t required to have a reasonable suspicion of the presence of an illegal substance to use a drug sniffing dog at a traffic stop.

In the underlying case, a man named Roy Caballes was stopped for speeding. During the stop, the police officer had a drug sniffing dog with him. The dog smelled the presence of marijuana in Mr. Caballes’ vehicle, and the officer arrested Mr. Caballes for marijuana possession. The trial court convicted Mr. Caballes for drug possession.

However, the Illinois Supreme Court reversed the trial court’s conviction, stating it was unreasonable for the police officer to use a drug sniffing dog when he stopped Mr. Caballes for speeding without having any other suspicion that Mr. Caballes had committed a more serious crime.

When the case reached the Supreme Court, however, the Court disagreed, stating that it’s not a violation of an individual’s Fourth Amendment right against unreasonable searches and seizures for the police to use a drug sniffing dog without any reasonable suspicion that the person has committed a crime.

In its decision, the Court’s majority stated that the Fourth Amendment isn’t implicated in drug sniffing dog cases, as these dogs only detect the presence of illegal substances, such as drugs.

According to the Court, no one has a reasonable expectation of privacy when it comes to illegal substances. As a result, the Court ruled that police don’t need a reasonable suspicion that someone has committed a crime before they bring a drug sniffing dog on the scene.

What Police Can Do with a Drug Sniffing Dog at a Traffic Stop

Under Caballes, police are allowed to use a drug sniffing dog at a routine traffic stop, however, police are limited to walking the dog around the outside of a vehicle. They don’t need a reasonable suspicion that a crime has been committed to do this.

If the dog signals it has detected the presence of an illegal substance, police then have probable cause to perform a search of the vehicle.

On the other hand, police aren’t allowed to hold someone indefinitely until the drug sniffing dog arrives on the scene. Instead, they’re limited to detaining individuals including passengers during a traffic stop, for only as long as takes to conduct a normal, routine stop.

What constitutes a “normal” amount of time for a routine traffic stop is something of a gray area, but courts typically use a “reasonable person” approach when determining whether a stop went on too long. For example, they look at what an ordinary, reasonable person would consider an excessive amount of time for a typical traffic stop.

Basically, the police are only allowed to keep a person on the side of the road for as long as it takes to make the stop, gather information and write a speeding ticket. If they keep an individual longer just because they’re waiting for a drug sniffing dog to arrive, this is a violation of the Fourth Amendment.

If the police drag on a traffic stop for too long, and they make an arrest based on contraband detected by a drug sniffing dog, the court may determine that the search was unreasonable.

In these situations, the court may suppress any evidence gathered during the search, which could mean the entire case gets thrown out.

The Limits of the Caballes Ruling

The Supreme Court’s decision in Caballes doesn’t give police a blank check for using drug sniffing dogs in every situation. Instead, the Court’s ruling only applies to the use of drug sniffing dogs at traffic stops.

For example, Caballes doesn’t authorize the police to use drug sniffing dogs when they stop people on foot, or when someone is walking across a parking lot or crossing the street. The Fourth Amendment provides broad protection for an individual’s legitimate privacy interests, and the police must respect a person’s right to privacy.

If you’ve been charged with drug possession after the police used a drug sniffing dog at a traffic stop, contact an experienced Dallas criminal defense lawyer for drug crimes at the Broden & Mickelsen, LLP today.

Dallas Best Drug Defense Attorneys
Broden & Mickelsen, LLP
(T): 214-720-9552

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Prior results cannot and do not guarantee or predict a similar outcome with respect to any future case.


  1. https://www.oyez.org/cases/2004/03-923
  2. https://www.pbs.org/wgbh/nova/article/dogs-sense-of-smell/

Mick Mickelsen is a nationally recognized criminal trial attorney with more than 30 years of experience defending people charged with white-collar crimes, drug offenses, sex crimes, murder, and other serious state and federal offenses.