Guest Post by Lauren Williams, staff writer for Randolphwolf.com/blog
Dogs play a major role in the law enforcement operations. Dogs have a great sense of smell. According to experts, a dog’s sense of smell is up to a million times more sensitive than a human’s. They are used to sniff out bombs and narcotics. Scent dogs can detect human scent. The law enforcement officers use scent dogs to identify the criminals. The scent dogs could pick the guilty party out of a lineup based on the scent of something that was in contact with a person suspected of committing a crime. Is dog scent evidence alone sufficient for a conviction? The evidence experts and courts say that it is not sufficient.
On February 27, 2013, the Court of Criminal Appeals of Texas acquitted a defendant who was convicted by the trial court holding that dog scent evidence alone is not sufficient to support the conviction. (see Winfrey v. State, 2013). In Winfrey, the victim was a school janitor, murdered in 2004. The defendant, who was only 16 years at the time of the murder, was taken into custody after the enquiry that included dog-scent lineups and charged with two counts for capital murder and conspiracy. The Court held that the dog-scent evidence is only supportive and it cannot constitute itself as a conclusive evidence of guilt. If the State produced dog-scent evidence in a case, the State must produce other evidence to corroborate the dog-scent evidence to make a conclusion that the defendant has committed the crime.
Dog-scent evidence is inculpatory in nature. Inculpatory evidence means evidence that shows, or tends to show, a defendant’s involvement in a crime. In penal law, evidence that favors the prosecution’s case is called the inculpatory evidence. Exculpatory evidence means the evidence that shows the innocence of a defendant.
The supporters of the dog-scent lineup say that the dog-scent lineup is a most powerful tool for the law enforcement officers during their investigation. In dog-scent lineups, the dog walks along a line of tin cans that contain individual scent samples from possible suspects. It is similar to lineups in which a witness identifying a suspect from a group of people.
The law enforcement officers take scent samples from the possible suspects as well as others who are not involved in the crime. The dog is exposed to the scent from the items found at the crime scene and then walked by the line of tin cans that contain the scent samples. If the dog finds a matching scent, it gives a signal by barking.
Pursuant to a FBI report, the scent dogs are useful in establishing a connection to the crime. At the same time, the dog-scent lineups are criticized by many. They say that the procedures are not well-controlled and the possibilities of cross contamination are great in dog-scent lineups.
The dog experts say that the scent dogs commit mistakes unless they are trained well. Therefore, the scent-dog evidence is not always reliable. But it can be supportive if there is other corroborating evidence.