United States v. Johnson (1981)

In United States v. Johnson, 660 F.2d 21 (2d Cir. 1981), the defendant claimed that the drug dog's alert did not create probable cause to support the issuance of a search warrant for his luggage. Id. at 22. He argued that the dog was "incapable of distinguishing between the actual presence of drugs in a container and the residual odor when the controlled substances are no longer there...." Id. The Second Circuit rejected that contention as a misapprehension of the concept of probable cause. It said, id. at 22-23: "Appellant's argument with respect to the problem of a dog detecting only the residual odors as opposed to the drugs themselves misconstrues the probable cause requirement. Absolute certainty is not required by the Fourth Amendment. What is required is a reasonable belief that a crime has been or is being committed."