The exclusionary rule serves to deter police from violating the Fourth Amendment to the United States Constitution. (Arizona v. Evans (1995) 514 U.S. 1, 10-11 [115 S. Ct. 1185, 1190-1191, 131 L. Ed. 2d 34, 44]; New York v. Harris (1990) 495 U.S. 14, 20-21 [110 S. Ct. 1640, 1644-1645, 109 L. Ed. 2d 13, 22]; and see United States v. Janis (1976) 428 U.S. 433, 458, fn. 35 [96 S. Ct. 3021, 3034, 49 L. Ed. 2d 1046, 1063].) In a trio of opinions, the Ninth Circuit has stated that "if application of the exclusionary rule in a particular situation 'does not result in appreciable deterrence, then, clearly, its use . . . is unwarranted.' " (United States v. Lopez-Martinez (9th Cir. 1984) 725 F.2d 471, 476, quoting United States v. Janis, supra, 428 U.S. at p. 454 [96 S. Ct. at p. 3032, 49 L. Ed. 2d at p. 1060]; accord, U.S. v. Medina (9th Cir. 1999) 181 F.3d 1078, 1082; U.S. v. Basinger (9th Cir. 1995) 60 F.3d 1400, 1407.) In Lopez-Martinez, border patrol agents arrested the defendant in 1982 for importing and possessing heroin with intent to distribute it. At trial, the prosecution introduced evidence that in 1974 Drug Enforcement Administration (DEA) officials had stopped and confiscated two vehicles containing 680 pounds of marijuana. The defendant had told a DEA agent that he was to receive $ 1,000 for transporting the drugs. the government offered the evidence under Federal Rules of Evidence, rule 404(b) (28 U.S.C.) to show the defendant's knowledge and intent to import heroin. (United States v. Lopez-Martinez, supra, 725 F.2d at pp. 475-476.) On appeal, the Ninth Circuit rejected the argument that evidence from the 1974 arrest should have been suppressed. There was no evidence that the enforcement activities in the 1974 and 1982 incidents were related. Because "the agents in 1974 did not have the later 1982 proceedings in their 'zone of primary interest,' " the deterrent effect of excluding evidence from the 1974 incident was "too small to outweigh the cost to society of the loss of relevant and probative evidence in the 1982 proceeding." ( United States v. Lopez-Martinez, supra, 725 F.2d at p. 476.) In U.S. v. Basinger, supra, 60 F.3d 1400, the defendant was convicted of knowingly maintaining a place to manufacture methamphetamine and making methamphetamine in Yakima, Washington in 1992. at trial, the prosecution introduced evidence that police had found one and one-fourth gram of methamphetamine, $ 10,440 cash and a 90-pound drum of red phosphorous in the trunk of the defendant's car in a search during a 1991 traffic stop and arrest of the defendant in California. The Ninth Circuit rejected the claim that evidence from the 1991 search should have been suppressed. There was no evidence of bad faith or collusion between the California and Washington officers in the separate matters--the California officer did not have the Washington incident within his " ' "zone of primary interest." ' " ( U.S. v. Basinger, supra, 60 F.3d at p. 1407, quoting United States v. Lopez-Martinez, supra, 725 F.2d at p. 476, and citing United States v. Janis, supra, 428 U.S. at p. 458 [96 S. Ct. at p. 3034, 49 L. Ed. 2d at p. 1063].) Thus, even if the 1991 search were illegal, exclusion of the evidence from that arrest would be "unwarranted because exclusion would have a minimal deterrent effect." (Basinger, supra, at p. 1407.) In U.S. v. Medina, supra, 181 F.3d 1078, the defendant was convicted in federal court for bank robberies occurring between September 1995 and May 1996. The court denied the defendant's motion to suppress a gun found in a luggage search by Los Angeles International Airport police and another gun found by Los Angeles Police Department officers pursuant to a traffic stop for expired registration tags. The gun possession charge arising from the traffic stop was dismissed after the state court suppressed the gun as the product of an illegal search. The federal investigators who arrested the defendant for the bank robberies obtained both guns from the Los Angeles Police Department. On appeal from the conviction for the bank robberies, the Ninth Circuit rejected the defendant's argument that the admissibility of the guns depended on an assessment of the legality of the prior searches. ( U.S. v. Medina, supra, 181 F.3d at p. 1081.) This was so even though the guns at issue were the same weapons used in the bank robberies. Again, the court held that "absent any threshold showing of a connection or 'nexus' in time, place, or purpose between the searches and the subsequent prosecution, there is no appreciable deterrent purpose in suppressing the evidence." ( Id., at p. 1082.) The prosecution made no showing of collusion by the distinct police agencies in conducting the various searches so as to obtain the federal bank robbery conviction.