Law enforcement agencies in Pennsylvania and across the United States routinely use drug dogs to “alert” officers to the presence of narcotics in vehicles. However, studies have found that a significant percentage of these alerts fail to yield any drugs once the vehicle is searched.

For example, a Kentucky newspaper investigated traffic stops in Louisville since Jan. 1, 2017, and found that authorities failed to find drugs in 45% of vehicle searches in which K-9 officers signaled the presence of drugs. Of the searches that yielded drugs, most involved small amounts of marijuana, including single joints, partially smoked joints or shake, which is leftover stems or plant residue. However, some searches yielded various amounts of cocaine, methamphetamine or heroin. Overall, 42 people were taken into custody, and approximately 12 defendants were charged with drug trafficking. Meanwhile, a 2011 investigation by the Chicago Tribune found that just 44% of drug dog alerts in suburban Chicago led to the seizure of drugs or drug paraphernalia.

According to experts, these results do not mean that drug dogs are inaccurate. Instead, it may mean that the dogs are detecting trace amounts of drugs that are too small for officers to find or smelling residue from drugs that were previously in the car. Studies have also found that bias on the part of a K-9’s handler can lead dogs to wrongly signal the presence of drugs.

Individuals facing drug possession charges might need the assistance of a criminal defense attorney. The attorney could protect a defendant’s rights throughout all court proceedings and work to build a strong defense against the allegations. Depending on the details of the case, these efforts could lead to the charges being reduced or dismissed.