APPEAL FROM THE UNITED STATES DISTRICT COURT FOR THE DISTRICT OF MAINE. Hon. John A. Woodcock, Jr., U.S. District Judge.
Jonathan G. Mermin, with whom Preti, Flaherty, Beliveau & Pachios, LLP was on brief, for appellant.
Margaret D. McGaughey, Assistant United States Attorney, with whom Thomas E. Delahanty II, United States Attorney, District of Maine, was on brief, for appellee.
Before Lynch, Chief Judge, Thompson and Barron, Circuit Judges.
THOMPSON, Circuit Judge.
Working on a tip from a confidential informant, police searched defendant-appellant Richard Graf's home, turning up marijuana and an illegal gun. Graf was subsequently indicted on drug and firearm charges.
He moved in a pre-trial motion to suppress the seized evidence, arguing to a Maine federal magistrate judge that to sweet-talk a state court justice of the peace into signing off on the search warrant application, a police detective sugarcoated the facts in his sworn statement accompanying it. As part of his motion to suppress, Graf also requested an evidentiary hearing to challenge the affiant-detective's credibility.
Neither the magistrate judge nor the district court was convinced and denied the motion. Graf now appeals the denial, arguing that he was entitled to a full hearing to challenge the detective's veracity, and the magistrate judge improperly allowed the government to investigate itself before deciding his motion to suppress.
Despite a valiant effort, we affirm the lower court.
The Controversial Warrant Affidavit
In April 2011, Carl Gottardi, a detective lieutenant for the Somerset County Sheriff's Department in Maine, applied for a warrant to search Graf's home. The warrant application was supported by Gottardi's sworn statement, to which we'll refer from now on as " the Graf affidavit."
In the Graf affidavit, Gottardi attested he had probable cause to believe Graf was hiding marijuana and other drug accoutrements in his home, based on information Gottardi received from a confidential informant called " 11-25." 11-25 " ha[d] been a very reliable informant . . . for the past several years," and had helped " obtain numerous drug search warrants, . . . with numerous persons being charged and convicted of various . . . drug offenses," Gottardi swore. 11-25 had " also provided other law enforcement officials with reliable drug related information in the past."
Specific to this case, Gottardi also wrote in the affidavit that 11-25 relayed his personal knowledge that " for several years  Graf has continually sold large amounts of marijuana," describing the location of the " camp type residence" where Graf sold his " high grade, commercial type" stuff. Relying on Gottardi's affidavit, a state Justice of the Peace signed off on the warrant, and during the search of Graf's home, police found marijuana plants and an unregistered short-barreled shotgun. Not surprisingly, Graf was indicted on federal firearms possession and drug charges.
Graf's Franks Motions
In Franks v. Delaware, 438 U.S. 154, 155-56, 98 S.Ct. 2674, 57 L.Ed.2d 667 (1978), the Supreme Court held that a defendant is entitled to an evidentiary hearing to " challenge the veracity of a sworn statement used by police to procure a search warrant," if " the defendant makes a substantial preliminary showing that a false statement knowingly and intentionally, or with reckless disregard for the truth, was included by the affiant in the warrant affidavit, and if the allegedly false statement is necessary to the finding of probable cause." In August 2011, Graf asked the federal trial court for one of these so-called Franks hearings, arguing that he should be able to test the veracity of the statements Gottardi made in his warrant affidavit. Graf maintained via a sworn-to affidavit that at best, Gottardi embellished 11-25's reliability, but more likely, either Gottardi or the informant was simply lying. In addition to a hearing, Graf also asked that the evidence seized from his home be suppressed. Other than his affidavit, Graf supported his motion with nothing further.
A magistrate judge denied the motion because, as she put it, Graf did " not allege, [or] . . . attempt to make a substantial preliminary showing, that  Gottardi knowingly and intentionally made false statements in the search warrant affidavit or included statements in reckless disregard of the truth." Rather, the magistrate judge decided, Graf " relie[d] entirely on the theory that the confidential informant gave Gottardi inaccurate information," which was not enough for a Franks hearing.
Graf's team was undeterred, and his new lawyer decided to get to the bottom of things himself by digging up all the warrant applications filed by the Somerset County Sheriff's Department from April 2009 through April 2012 and searching for all references to " 11-25." Turns out, there were none, that is, no warrant applications filed prior to April 2011 (which was when Gottardi got the warrant to search Graf's home) naming " 11-25" as an informant. " 11-25" did appear, however, in two of the warrant applications filed after Graf's, but in each of the three affidavits where " 11-25" was mentioned, the informant's background and history as a tipster were described a little differently.
Armed with this new information, Graf marched back into court and filed a second motion to suppress and request for a Franks hearing. This second go-round, Graf argued that he now had proof Gottardi " displayed a reckless disregard for the
truth by exaggerating CI 11-25's reliability and use in the past." 
The government fired off an explanation, though, and in support of its opposition to the motion, submitted a supplemental affidavit from Gottardi describing his " practice to periodically change the identifying numbers assigned to confidential informants." Gottardi also claimed that " the person designated CI 11-25 in the Graf search warrant has been assigned four identifying numbers during the course of" his work with Gottardi. In addition, " [o]ccasionally, identifying numbers will be re-used for different persons," Gottardi swore.
Graf shot back, arguing that even if Gottardi was telling the truth about these so-called practices of his, " [b]y assigning the same CI numbers to three different individuals on three different drug cases over a five month period, Gottardi is misleading those officials who are tasked with reviewing affidavits in support of search warrants." Gottardi's unconventional practice, Graf urged, " is meant to enhance the credibility of the [informant] whose number repeatedly ...