In United States v. Carey, 836 F.3d 1092, 1093 (9th Cir. 2016), federal agents secured a wiretap order under the Wiretap Act, 18 U.S.C. §§ 2510-2522. The order was based upon evidence that Ignacio Escamilla Estrada ("Escamilla") used the number to smuggle and distribute drugs. Carey, 836 F.3d at 1093. During the seven-day wiretap, the agents realized that Escamilla was not the one using the phone. Id. Nevertheless, believing that those on the phone may be connected to Escamilla, the agents continued listening. Id. Authorities ultimately identified Michael Carey as the unknown speaker. Id. The investigation revealed that Carey was not involved with Escamilla. Id. at 1094.
Carey moved to suppress all of the evidence derived from the use of the wiretaps, arguing that the government had unlawfully relied on the Escamilla order to justify the independent and unrelated use of wiretap surveillance against Carey. Id. The district court denied Carey's motion, explaining that (1) the government had complied with the statute for the wiretap order against Escamilla, and (2) that there was no requirement for a separate showing of necessity once the agents concluded that T-14 was not used by Escamilla because the agents reasonably believed that the callers and calls might be affiliated with Escamilla or other offenses. Id. at 1095.
The Wiretap Act requires (1) "probable cause that a particular offense has been or will be committed," (2) "'necessity' for the wiretap by showing that traditional investigative procedures did not succeed or would be too dangerous or unlikely to succeed if tried," and (3) "adopt minimization techniques to reduce to a practical minimum the interception of conversations unrelated to the criminal activity under investigation." Id. (internal citations omitted). On appeal, Carey argued that the government did not comply with these statutory requirements as to him or his coconspirators—instead demonstrating probable cause and necessity only as to Escamilla's conspiracy. Id. The government countered that "the agents could continue monitoring the wiretap even after realizing that they were not listening to the target conspiracy" because language in the wiretap order authorized "interception of drug calls by 'others yet unknown.'" Id. at 1097. Moreover, the government argued, "the Wiretap Act permits the collection of evidence of other crimes under 18 U.S.C. § 2517(5)." Id. at 1098.
The Carey court was unmoved by the government's arguments. It explained that after reviewing of the record, it found that the provisions of the wiretap order indicated that any unknown people referred to in the order must be involved with the Escamilla conspiracy. Id. The court continued that the statute allows for the use of communications relating to other crimes "only when officers are 'engaged in intercepting wire, oral, or electronic communications in the manner authorized herein.'" Id. (citing 18 U.S.C. § 2517(5)).
Instead of adopting Carey's argument, however, the court found a middle ground. Citing what it described as dicta from the Seventh Circuit, the court observed that
[i]t is true that if government agents execute a valid wiretap order and in the course of executing it discover that it was procured by a mistake and at the same time overhear incriminating conversations, the record of the conversations is admissible in evidence. It is just the "plain view" doctrine translated from the visual to the oral dimension. . . . [O]nce the mistake is discovered, the government cannot use the authority of the warrant, or of the [wiretap] order, to conduct a search or interception that they know is unsupported by probable cause or is otherwise outside the scope of the statute or the Constitution.
Id. at 1096-97 (citing United States v. Ramirez, 112 F.3d 849, 851-52 (7th Cir. 1997)). The Carey court then analogized its case to Maryland v. Garrison, in which officers secured a search warrant "for Lawrence McWebb's residence at '2036 Park Avenue third floor apartment.'" Id. at 1097 (citing Garrison, 480 U.S. 79, 80 (1987)). Upon entering the apartment, the officers at first "reasonably concluded that the third floor was only one apartment unit" but soon discovered that the floor was divided into two apartments. Id. (citing Garrison, 480 U.S. at 80). Prior to that discovery, the officers had seen contraband in Garrison's apartment. Id. (citing Garrison, 480 U.S. at 80). While the search prior to noticing the realization was valid, the Carey court explained, "the officers 'were required to discontinue the search of respondent's apartment as soon as they discovered that there were two separate units on the third floor and therefore were put on notice of the risk that they might be in a unit erroneously included within the terms of the warrant.'" Id. (citing Garrison, 480 U.S. at 87). Accordingly, the Carey court held that
the police may use evidence obtained in "plain hearing" when they overhear speakers unrelated to the target conspiracy while listening to a valid wiretap. . . . However, the agents must discontinue monitoring the wiretap once they know or reasonably should know that the phone calls only involved speakers outside the target conspiracy.
Id. at 1093-94.
Applying the holding to the present case, the court vacated the denial of the motion to suppress and remanded to determine what evidence was lawfully obtained in "plain hearing." Id. at 1094. A brief dissent agreed "that the government may use evidence obtained from a valid wiretap until officers know or should know they are listening to conversations outside the scope of the wiretap order." Id. at 1100. The dissent would not remand, however, because Carey failed to demonstrate that any evidence should be suppressed under the "plain hearing" rule and a remand would "give Carey a mulligan." Id. at 1101.