In United States v. Race (1st Cir. 1976) 529 F.2d 12, an expert dog handler using a detector dog made an exploratory search of 300 crates at the American Airlines warehouse located at Logan Airport. Subsequent to the dog's alert at two crates, the agent inserted a knife into one of the crates and detected the odor of marijuana on the knife blade. The consignee of the crates, having identified himself, was approached regarding consent to search the crates, which he was held to have given. The search after consent uncovered marijuana. The appellate court in Race specifically did not decide if the use of the knife was a prohibited search. ". . . Even assuming that agent Murphy violated the fourth amendment by inserting the knife into one of the crates, a question we do not decide, we do not think exclusion of the marijuana in the crates would be warranted." (At p. 15.) In United States v. Race (1st Cir. 1976) the arrest was by customs at port of entry; the court approved the use of detector dogs, although it said that a trained dog's reaction alone is not sufficient probable cause for "arrest" (p. 14).