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Dog Sniffing Searches and the Fourth Amendment of the U.S. Constitution: Have Your Privacy Rights Against Unreasonable Search and Seizure Gone to the Dogs in Texas?

Dog sniffing car after 9/11 terrorist attack on the Pentagon

Dogs are great, and no one is going to challenge that dogs have the ability to hear and to smell things that human beings cannot. Dogs, after all, have the ability to hear sounds at a much larger frequency range than humans — from 67 Hz to 45 kHz (humans max out at 23 kHz). Their sense of smell is even more advanced comparatively: scientists explain a dog’s sense of smell as being 100 times more powerful than a humans, with dogs having 220,000,000 olfactory receptors compared to a human nose’s 5,000,000.

No wonder that dogs have been used to sniff for bombs by the U.S. Military (like in the image above) or search for survivors after earthquakes or tornadoes. Dogs have saved lives through their superior senses of smell and hearing and they deserve respect for their contributions.

Dogs, Evidence, and the Fourth Amendment – It’s the Defense Lawyer’s Fight These Days

However, when dogs are used by law enforcement to search in situations where someone’s freedom and liberty are at stake, it’s extremely important to make sure that constitutional protections are maintained, such as the Fourth Amendment’s protection against unreasonable search and seizure.

Dogs are not machines: will the dog make mistakes? Will the dog seek to please its owner at the expense of accuracy? Can the dog be trained to respond as his master wishes as opposed to how his surroundings suggest?

Many have argued that the superior scent ability of police dogs cannot justify a disregard of longstanding evidentiary standards for reliability.  Court cases have been hard fought on the use of canine evidence in criminal trials because criminal defense lawyers are adamant that dog-based evidence should not be admissible in criminal prosecutions.

Unfortunately, prosecutors have won their arguments that dog sniffing evidence should come into evidence more often than not.

For instance, in the case of Illinois v. Cabelles, the U.S. Supreme Court found that the Fourth Amendment is not violated when, during a routine traffic stop by law enforcement, a dog is used to sniff for drugs as long as the dog’s sniffing around the vehicle does not unreasonably prolong the time taken by the traffic stop.

Then, in Florida v. Harris, the U.S. Supreme Court held that the Florida Supreme Court was wrong to hold that state prosecutors had to establish the reliability of a “scent hound” by admitting the drug dog’s field performance log. With this ruling, the High Court found that prosecutors need only show that a drug detection canine has been trained in some manner to sniff for drugs in order to be given legal status as a canine expert and any evidence discovered in the dog’s sniffing search as admissible.

This, even though there are real and valid concerns that a dog’s trainer can suggest the dog’s behavior (consciously or unconsciously) or that a particular dog may have a history of false positives in past searches.

Which means it is the criminal defense’s lawyer’s job now to fight, and fight hard, against evidence located by a “scent hound” law enforcement dog which is being advanced by the prosecution against an individual accused of a serious crime.

Dogs During Traffic Stops: the “Sniff Search” for Illegal Drugs or Contraband

Today, if someone is pulled over by the police in a routine traffic stop, they may be surprised to see a police dog involved in the traffic stop, as the dog is used to sniff around their car, truck, or SUV.

It’s a question of the limitation of freedom during a traffic stop: traffic stops cannot take too long, say 20 minute max, and the dog must complete any sniffing of the outside of the vehicle during that time frame.

Moreover, the dog can only sniff the outside or exterior of the vehicle — it’s only if the dog alerts to a potential scent of illegal drugs that the police officer arguably has “probable cause” to enter the interior of the vehicle and have the drug dog sniff the inside of the car, truck, or SUV, for drugs.

Additionally, drug dogs can sniff cars parked in parking lots or other public places whenever the police think it’s a good idea: it is not a “search” with constitutional protections for a police officer to have a drug dog sniff for drugs in a public area.

Defense Concerns About Drug Dog Search Evidence

Criminal defense lawyers here in Dallas, and Texas, and across the country, are united in their concerns about the use of police dog alerts as a means of circumventing traditional Fourth Amendment search protections by law enforcement in order to gain access to persons, vehicles, homes, and elsewhere in order to search for potential evidence to be used against an individual in a criminal prosecution.

Defense concerns include the reality that drug residue is commonplace — just because a dog alerts to drug residue does not mean that there is a justifiable reason to search someone or their car. Drug residue is in lots of places and may exist in cars or on luggage or tires for a very long time.

Additionally, sometimes dogs seem to “alert” to something when there’s nothing there: “false alerts” happen all the time.

Finally, it is up to the police officer to interpret the dog’s behavior in order to establish that there is a reason for the police to do something more involving the search for evidence. Was there really an alert? Was there a cue signaling the dog, consciously or unconsciously, by the officer or trainer?


For more information, check out our FAQ explaining “10 Things You Should Know When Your Car Is Pulled Over in the State of Texas” and recent Case Results which include Michael Lowe’s successful Motion to Suppress evidence obtained in a drug dog sniffing situation, where a felony money laundering charge was reduced to a misdemeanor charge and the money taken during the search was returned to the defendant.




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