By Virginia Tehrani, Esq.

How to chip away at a K-9’s credibility

The nose knows, or does it?

A dog’s nose is a powerful thing. This is why law enforcement and the military use carefully trained dogs to detect drugs, bombs, other explosives, missing persons, and missing things. Today, police also use dogs to detect the presence of guns based on the smell of gunpowder and its owner’s scent on the gun.

Even the United States Supreme Court has recognized and accepted the use of drug-sniffing dogs for Fourth Amendment searches and seizures. Given a good set of credentials, a dog’s positive alert for drugs can establish probable cause to search a vehicle, home, or other containers and objects.

However, not every dog is sufficient to establish probable cause. Nor is every search.

The crucial question for any defense attorney challenging the legality of a search after the use of a dog sniff is whether the dog’s positive alert is reliable. See [my earlier blog] for a review of the constitutionality of dog sniff evidence for establishing probable cause for officers to perform a search.

Defense attorneys should gather evidence and testimony from the K-9’s human handler about the team’s training, certifications, experience, and record to question the team’s expertise. As a criminal defense lawyer, you can chip away at the quality of the dog’s positive alert.

Is the K-9 handler an expert?

Because it takes special training and experience to use a canine for law enforcement, courts should only consider a K-9 handler’s testimony if that handler is certified as an expert in dog handling – at least with that particular dog.

As with all expert testimony under Rule 702 of the Federal Rules of Evidence (most states have a similar rule), a dog handler may testify as an expert only if they have the proper “knowledge, skill, experience, training, or education” in the field for which they are testifying. That expertise must be weighed by the court based upon Rule 702’s determining factors that the witness’s testimony is:

  • Based on specialized training or knowledge that will help explain a factual issue in the case;
  • Based on sufficient facts or data;
  • Based on reliable principles, procedures, and methods; and
  • Based on the witness having reliably applied those principles and methods to the particular facts of the present case.

The bar is set high. Even if the K-9 handler has the proper knowledge, skill, experience, training, or education in dog sniffs, that handler must also meet four more standards for expert testimony. These qualifiers are not optional, and defense attorneys should demand strict proof of these standards.

The key to all canine evidence is reliability. Is the dog’s positive alert and its handler’s interpretation of that alert reliable enough to establish probable cause?

A defense attorney should question the reliability of all parties involved in the dog’s detection of drugs, bombs, guns, or other items. Is the dog reliable? Is the handler reliable? And finally and most importantly, is the K-9 team reliable?

How reliable is the dog?

If the dog’s credentials are good, then the search will be upheld as a legal search with probable cause. The higher a dog’s success rate in finding drugs based on its training, the more reliable the dog will be.

The defense should ask for copies of all documentation on the dog’s training and experience. Obtain its certificates, a list of items the dog has been trained to detect, how long the dog has been working in this field, and its ratio of positive to false alerts. Ask how long the dog’s training lasted, what it was trained to do, the methods and procedures it learned to detect drugs, and whether it receives continuing training.

If possible, obtain training manuals from the police department that describe the dog’s training. Compare those procedures to the training used in other law enforcement communities and see how well they match.

Not all dogs have solid records, and not all dogs have been vetted, so question everything.

How reliable is the handler?

Even if the dog is reliable, the human handler may not be. Defense attorneys should question the handler’s experience and training, too.

What training and experience does the handler have with dog sniffs and searches? How much training and education does the handler have, and what type of training has the handler received? Does the handler have certifications apart from or with its canine partner? How much hands-on experience does the handler have in controlled settings and in the field?

Reading what a dog is trying to say is like reading a foreign language. The handler must know how to interpret the dog’s reactions. Not all dogs use the same body language to alert their handlers that they are detecting a scent they are trained to recognize.

There is no lingua franca in the dog sniff world. While one dog may give a positive sign that they’ve caught a whiff of something by sitting and whining, another dog may simply sit and point. Other dogs pant or bark. Find out which behavior the dog uses and whether the handler has experience interpreting his partner’s behaviors.

Also find out how the dog’s response is different when it is smelling drugs versus when it smells other odors, like food and spices.

How reliable is the team?

Defense attorneys should also gauge the dog handler’s experience and training with his partner. If a dog is trained and the handler is trained, those facts alone do not prove that the two have trained together and gained enough experience in the field as a team. Normally, handlers do not use each other’s partners in the field, because it takes specialized training and a close relationship between the dog and its handler to create a powerful team. The canine handler needs to know how the dog reacts in specific law enforcement settings in order to accurately understand and interpret his partner’s reaction.

For example, I’ve questioned a handler’s expertise with the dog he used at a crime scene, because he did not use his own canine partner. Instead, he used another dog that night, and the outcome was questionable. The dog did not obey this new handler. Instead, he had to be told 13 times simply to sit by the side of the road. Also, the handler questioned his own interpretation of the dog’s actions, asking another officer if he’d improperly led the dog into making a positive alert. It didn’t help that the officer’s bodycam footage caught him asking himself whether the dog would be luckier in making a positive alert in this particular district than it normally had been.

Although the dog may have been properly trained and could make reliable positive alerts, this was not a well-oiled team.

While dog sniff evidence may be enough to establish probable cause, defense attorneys can and should question the K-9’s reliability and credibility before accepting the handler’s testimony at face value.

After all, not every dog passes the smell test.