Court Opinion

ID: 9353617
Source: CourtListenerOpinion
Date Created: 2023-01-12 15:00:53.89487+00
Date Added: 2024-06-11T17:09:42.442274
License: Public Domain

USCA11 Case: 20-12385     Document: 70-1       Date Filed: 01/12/2023   Page: 1 of 23

                                                   [DO NOT PUBLISH]
                                      In the
                 United States Court of Appeals
                          For the Eleventh Circuit

                            ____________________

                                   No. 20-12385
                            ____________________

        KAREN KALLEN-ZURY,
                                                      Petitioner-Appellant,
        versus
        UNITED STATES OF AMERICA,

                                                     Respondent-Appellee.

                            ____________________

                  Appeal from the United States District Court

                        for the Southern District of Florida

          D.C. Docket Nos. 1:17-cv-21269-JEM and 1:12-cr-20757-JEM-1
                          ____________________
USCA11 Case: 20-12385      Document: 70-1      Date Filed: 01/12/2023     Page: 2 of 23

        2                      Opinion of the Court                 20-12385

        Before JORDAN, LUCK, and LAGOA, Circuit Judges.
        PER CURIAM:
               After a five-week trial, a jury found Karen Kallen-Zury guilty
        on various counts relating to Medicare fraud. During the trial, the
        jury heard from many witnesses and was presented with many doc-
        uments corroborating the government’s theory of the case and dis-
        crediting Kallen-Zury’s testimony. Following the district court’s
        denial of her 28 U.S.C. § 2255 motion to vacate her conviction,
        Kallen-Zury appeals the denial and argues that her trial counsel
        should have called several witnesses in her defense, that counsel’s
        failure to do so constituted ineffective assistance of counsel, and
        that we should vacate her conviction and grant her a new trial.
              With the benefit of oral argument, and for the reasons ex-
        plained below, we find that trial counsel’s decision not to call these
        witnesses did not prejudice her. Accordingly, we affirm.
            I.     FACTUAL AND PROCEDURAL BACKGROUND
                         A.     Underlying Criminal Case
               This is the fourth time Kallen-Zury has come before this
        Court regarding her trial. We outlined the facts of this case in our
        decisions denying Kallen-Zury’s prior appeals. United States v.
        Kallen-Zury (Kallen-Zury I), 629 F. App’x 894 (11th Cir. 2015);
        United States v. Kallen-Zury (Kallen-Zury II), 710 F. App’x 365
USCA11 Case: 20-12385          Document: 70-1          Date Filed: 01/12/2023          Page: 3 of 23

        20-12385                    Opinion of the Court                                  3

        (11th Cir. 2017); see also United States v. Kallen-Zury (Kallen-Zury
        III), 736 F. App’x 848 (11th Cir. 2018). 1
               “Kallen-Zury co-owned and operated Hollywood Pavilion
        (‘HP’)—a mental health facility that included both inpatient and
        outpatient treatment programs”—as well as “a nursing home and
        rehabilitation center named Hollywood Hills (‘HH’) on the same
        premises.” Kallen-Zury I, 629 F. App’x at 897. During her tenure
        at HP, the facility, which received Medicare reimbursements, paid
        recruiters to bring patients to HP. Id. This is illegal. Id. “The
        backbone of the government’s case was the testimony of several
        patient recruiters”—“Keith Humes, Jean Luc Veraguas, Mathis
        Moore, Curtis Gates, and Gloria Himmons, who worked as a sub-
        recruiter under Humes”—“who pleaded guilty to Medicare fraud
        related to HP and other facilities.” Id.
               “These recruiters would find patients from as far away as
        Maryland and would pay to have the patients ride buses down to
        HP in Hollywood, Florida.” Kallen-Zury II, 710 F. App’x at 367.
        “Most of the[se] patients were drug addicts who did not need the
        psychiatric services offered at HP.” Id. Accordingly, “the conspira-
        tors often falsified the patients’ records to reflect serious psychiatric
        problems or told the patients to [say they had] psychiatric issues

        1 Kallen-Zury has acknowledged that “the actual testimony that was presented
        at the initial trial in 2013 has been fairly presented in the prior opinions of this
        Court,” although she disputes the testimony’s truthfulness.
USCA11 Case: 20-12385     Document: 70-1      Date Filed: 01/12/2023    Page: 4 of 23

        4                      Opinion of the Court               20-12385

        upon admission” to HP. Id. HP would then pay the recruiter for
        each patient the recruiter sent to its facility. See id. at 367–68.
                “Additionally, HP . . . only admit[ted] patients who had
        enough days on their Medicare plans to have their treatment peri-
        ods paid for by the government.” Kallen-Zury I, 629 F. App’x at
        897. When the Medicare money ran out for a patient, the facility
        would stop treatment and dismiss the patient. Id. “Through this
        scheme, HP filed tens of millions of dollars in fraudulent claims to
        Medicare.” Id. “Some . . . recruiters also ran halfway houses and
        made extra money when HP referred discharged patients to those
        facilities.” Id.
               “At trial, the recruiters explained that HP had them enter
        into contracts that stated they were providing either ‘case manage-
        ment’ or ‘marketing’ services.” Kallen-Zury II, 710 F. App’x at 367–
        68. “HP also asked the recruiters to submit reports documenting
        their purported performance of these services.” Id. at 368. “The
        recruiters’ reports, however, were false,” as the recruiters “were
        never asked to and never did provide these other services.” Id. “In-
        stead, they were paid solely to refer patients.” Id.
               Several recruiters, each of whom testified under a grant of
        immunity, claimed to have discussed with Kallen-Zury how HP
        would pay them to recruit patients. Some recruiters also claimed
        that they discussed their recruiting efforts with other HP employ-
        ees. And Himmons testified that she discussed recruiting patients
        for HP with Kallen-Zury herself.
USCA11 Case: 20-12385          Document: 70-1         Date Filed: 01/12/2023          Page: 5 of 23

        20-12385                    Opinion of the Court                                 5

               The government also produced various documents at trial,
        including a “patient register” that tracked which patients were re-
        ferred by which recruiters. 2 The government additionally pre-
        sented the testimony of Dr. Gumer to explain that most of the pa-
        tients admitted to HP did not need psychiatric treatment, either
        because they only had substance abuse issues or because they were
        homeless.
               The defendants, including Kallen-Zury, argued “that they
        acted in good faith and believed the recruiters were providing law-
        ful ‘marketing’ services.” Kallen-Zury I, 629 F. App’x at 897. “They
        argued that HP’s lawyers drafted the contracts with the recruiters
        and instructed HP’s management [on] how to ensure that their
        agreements with the recruiters fell within statutory and regulatory
        ‘safe harbor’ provisions.” Id. at 897–98.

        2 At trial, an agent testified that the patient register was found on Kallen-Zury’s
        office computer, which Kallen-Zury denied maintaining and having a copy of,
        prompting the government in closing to use this contradiction to attack her
        credibility. “The prosecutor sarcastically called her ‘unlucky’ for having such
        an important document on her computer without even knowing it.” Kallen-
        Zury I, 629 F. App’x at 898. “After [the] trial, the government realized that the
        disc containing the register had been mislabeled by someone from the Depart-
        ment of Health and Human Services.” Id. “Although the prosecutors and the
        lead investigator did not know it, agents had found the document on the com-
        puter of another HP employee.” Id. This discovery prompted Kallen-Zury to
        move for a new trial, which the district court denied. Id. We affirmed, finding
        that there was no harmful error in this testimony, given the weight of evidence
        against her. Id. at 899–900, 915. This issue has therefore been resolved and is
        not part of the current appeal.
USCA11 Case: 20-12385      Document: 70-1      Date Filed: 01/12/2023     Page: 6 of 23

        6                      Opinion of the Court                 20-12385

               After the government rested, trial counsel for Kallen-Zury,
        Michael Pasano—who had implied in his opening statement that
        he would call several witnesses—ended up only calling Kallen-
        Zury as a fact witness. 3 Pasano told the jury that they would hear
        testimony discussing admission practices for people with mental
        health issues along with substance abuse issues, and testimony dis-
        cussing the operation of HP. Ultimately, Pasano made the decision
        to put Kallen-Zury on the stand first to try to catch the government
        off guard at the end of its four-week case. The theory was that the
        government was so focused on its own witnesses, that it may have
        been unprepared to cross-examine Kallen-Zury. Pasano hoped to
        get her off the stand in one day without the government impugn-
        ing her credibility too much, as her credibility was the key to Pas-
        ano’s theory of the case: that Kallen-Zury attempted to comply
        with all laws in good faith. Pasano discussed this strategy with
        Kallen-Zury during trial.
               On the stand, Kallen-Zury testified that she thought these
        recruiters constituted legitimate marketing services for the hospi-
        tal, a belief which she claimed HP’s attorneys verified. After
        Kallen-Zury finished testifying, Pasano introduced some docu-
        ments and a summary witness that he believed would not under-
        mine Kallen-Zury’s testimony.

        3 Pasano
               also called two character witnesses and one summary witness who
        summarized HP’s financial transactions.
USCA11 Case: 20-12385      Document: 70-1      Date Filed: 01/12/2023     Page: 7 of 23

        20-12385               Opinion of the Court                         7

               At a later 28 U.S.C. § 2255 hearing, Pasano stated that he
        made the “tactical choice” not to call the witnesses at issue in this
        appeal after Kallen-Zury testified in her own defense. Pasano did
        so because he did not think the remaining witnesses would signifi-
        cantly move the needle in the jury’s minds, and because calling
        those witnesses would provide an opportunity for the government
        to undermine Kallen-Zury’s testimony. As the trial progressed and
        the district court ruled on various issues, Kallen-Zury focused on
        asserting a “good faith” defense, a strategy which Pasano and
        Kallen-Zury discussed. In light of this defense, the credibility of
        Kallen-Zury was paramount. Kallen-Zury I, 629 F. App’x at 898.
        Because the credibility of Kallen-Zury was, in Pasano’s mind, criti-
        cal to victory at trial, he determined to focus on this good-faith de-
        fense and not put other fact witnesses on the stand that could un-
        dermine her credibility or muddy the waters.
               This strategy ultimately failed. The jury found Kallen-Zury
        and others guilty of all the charges against them, which for Kallen-
        Zury included: (1) conspiracy to commit health care fraud and wire
        fraud, 18 U.S.C. § 1349; (2) wire fraud, 18 U.S.C. § 1343; (3) health
        care fraud, 18 U.S.C. § 1347; (4) conspiracy to defraud the United
        States and to pay and receive kickbacks in connection with a federal
        health-care benefit program, 18 U.S.C. § 371; and (5) payment of
        kickbacks in connection with a federal health-care benefit program,
        42 U.S.C. § 1320a–7b(b)(2)(A). Kallen-Zury I, 629 F. App’x at 898.
        The judge sentenced Kallen-Zury to twenty-five years in prison.
                              B.     Previous Appeals
USCA11 Case: 20-12385       Document: 70-1       Date Filed: 01/12/2023      Page: 8 of 23

        8                        Opinion of the Court                   20-12385

                Kallen-Zury has come before this Court three times before
        this present appeal regarding her trial. After her conviction, Kallen-
        Zury filed a direct appeal. We affirmed her conviction and the dis-
        trict court’s denial of her motion for a new trial. See Kallen-Zury
        I, 629 F. App’x at 897, 899–900. We denied her motion for recon-
        sideration and for en banc review. Then, in 2016 and 2017, Kallen-
        Zury filed motions under Federal Rule of Criminal Procedure
        33(b)(1) for a new trial based on newly discovered evidence. The
        district court denied both motions, and we affirmed those decisions
        on appeal. Kallen-Zury II, 710 F. App’x at 371–73; Kallen-Zury III,
        736 F. App’x at 852 . We concluded that the new evidence Kallen-
        Zury highlighted did not warrant a new trial because it was largely
        cumulative or impeaching, and because it did not undermine con-
        fidence in the integrity of the verdict. See Kallen-Zury II, 710 F.
        App’x at 372–73; Kallen-Zury III, 736 F. App’x at 851.
                               C.     Motion to Vacate
               When those attempts failed, Kallen-Zury filed the § 2255
        motion to vacate at issue in this appeal, in which she detailed the
        prejudice she suffered at trial as a result of her trial counsel not call-
        ing various witnesses or presenting certain documents. In her
        § 2255 motion to vacate, Kallen-Zury argued that she should have
        a new trial because Pasano did not call Vala Wagie, Rocky Da-
        vidson, Angela Rosier, Aaron Danzig, Melvin Hunter, and Dr. Jef-
        frey Danziger as witnesses, and did not present various documents,
        including invoices from the law firm Baker Hostetler, which ad-
        vised HP and Kallen-Zury during this time. Kallen-Zury described
USCA11 Case: 20-12385      Document: 70-1     Date Filed: 01/12/2023     Page: 9 of 23

        20-12385               Opinion of the Court                        9

        in her motion the testimony each of these witnesses—who testified
        at the evidentiary hearing on the § 2255 motion—would have pro-
        vided had Pasano called them to the stand. We set forth the de-
        scriptions of testimony as follows.
               Vala Wagie, a risk management professional, would have
        provided character testimony, and her opinion that HP was run
        well. She would also testify that Kallen-Zury never asked her to
        hide or alter any documents, that Kallen-Zury was not in charge of
        clinical decisions at HP, and that all patients needed the treatment
        they received.
                Rocky Davidson, a certified public accountant who did out-
        sourced accounting for HP, would have testified that HP was not
        profitable enough to pay Kallen-Zury tens of millions of dollars and
        that a large portion of her income came from an unrelated nursing
        home not subject to this investigation.
               Angela Rosier would have testified that she oversaw patient
        charts and records, that she was unaware of any falsifications or
        alterations of those charts, that she was unaware of any mistreat-
        ment or unnecessary treatment of patients, and that Kallen-Zury
        had nothing to do with patient care or treatment. Rosier was also
        involved in gathering records to comply with the subpoena and
        would testify that she was unaware of any effort to obstruct justice.
              Aaron Danzig, an attorney, would have testified about his
        work complying with the government’s document requests to HP.
        He instructed Kallen-Zury on how to respond to those requests,
USCA11 Case: 20-12385      Document: 70-1      Date Filed: 01/12/2023     Page: 10 of 23

        10                      Opinion of the Court                 20-12385

        sent her newspaper articles and indictments as to other fraud inves-
        tigations as part of that advice, which the government later claimed
        was evidence of fraudulent intent, and he was working on having
        the original patient register scanned and sent to the government
        when the register was seized pursuant to a search warrant.
               Melvin Hunter, who oversaw the Admissions Department
        at HP and was tried separately, would have testified that patients
        who arrived at the facility were usually “pre-cleared” through an
        interview process—explaining the high admission rate the govern-
        ment claimed proved fraud—but that doctors at HP ultimately
        made the final admission decision. Hunter also would have testi-
        fied that he never told Himmons to lie nor told Himmons that
        Kallen-Zury was not satisfied with the number of patients Him-
        mons was referring to HP. Additionally, Hunter would have stated
        that Kallen-Zury did not have a role in altering the patient register,
        as it was his job, that he altered the columns in the patient register,
        and that the government seized those hard copy binders of patient
        registers during their search of the premises. Hunter also claimed
        he would have waived his Fifth Amendment rights if he testified at
        Kallen-Zury’s trial.
               Dr. Jeffrey Danziger, the defense’s medical expert, would
        have testified that each of the nineteen patients he reviewed were
        properly admitted, and that the patient charts were internally con-
        sistent, meaning doctoring them would have required dozens of
        people to be in on the fraud. He would also have explained the
        relationship between substance abuse and mental health issues,
USCA11 Case: 20-12385     Document: 70-1     Date Filed: 01/12/2023    Page: 11 of 23

        20-12385               Opinion of the Court                      11

        which was important because many patients at HP suffered from
        both and because the government cited to patients with substance
        abuse as proof of HP admitting patients that did not suffer from
        mental health issues.
               The district court referred Kallen-Zury’s motion to vacate to
        a magistrate judge. After three days of evidentiary hearings and a
        thorough review of the record, the magistrate judge recommended
        the motion to vacate be denied. The magistrate judge addressed
        each potential witness, summarized their testimony at the eviden-
        tiary hearings, and then made the following credibility and bias as-
        sessments.
               The magistrate judge found that Wagie was credible within
        the areas where she had knowledge during her employment at HP.
        But Wagie admitted she had no knowledge regarding HP’s mar-
        keting or recruiting operations. Additionally, the magistrate judge
        noted that Wagie had a “bias trend . . . in favor of Kallen-Zury.”
               The magistrate judge found Davidson’s testimony to be
        knowledgeable and credible. But given that he admitted all the
        payments shown on the government’s trial chart came from HP’s
        account, and not the nursing home’s account, his trial testimony
        that Kallen-Zury’s money came from sources other than HP would
        have had minimal value.
               Rosier was evasive and not credible, according to the magis-
        trate judge, particularly where she discussed signed blank treat-
        ment plan sheets in patient charts. After acknowledging that it was
USCA11 Case: 20-12385     Document: 70-1      Date Filed: 01/12/2023    Page: 12 of 23

        12                     Opinion of the Court                20-12385

        wrong to have signed blank patient sheets, she provided excuses
        and conflicting explanations about why examples of those signed
        blank sheets existed at HP, when confronted with multiple such
        instances during cross-examination.
                Danzig was generally credible but tainted by self-interest in
        justifying his handling of the government subpoenas, according to
        the magistrate judge. Therefore, the magistrate judge found that
        his testimony would have little value.
                Hunter was biased and inconsistent. According to the mag-
        istrate judge, he wanted to retaliate against the government given
        his prosecution in a parallel case. The magistrate judge also found
        Hunter’s assertion that he would have waived his Fifth Amend-
        ment rights and testified at Kallen-Zury’s trial was contradicted by
        the fact that he invoked those same rights when he was subpoe-
        naed by the grand jury in Kallen-Zury’s case. Additionally, when
        Kallen-Zury’s trial counsel asked Hunter to testify, his attorney
        stated Hunter would assert his Fifth Amendment rights if called to
        the stand.
               Dr. Danziger was credible, but his testimony was of limited
        value according to the judge. His review was only based on a few
        patients (nineteen out of thousands), and his opinions were predi-
        cated on the assumption that all the chart entries were true and
        accurate, even though he had no corroboration to support that as-
        sumption.
USCA11 Case: 20-12385      Document: 70-1      Date Filed: 01/12/2023      Page: 13 of 23

        20-12385                Opinion of the Court                         13

               The magistrate judge also considered Pasano’s explanation
        for his actions and found him to be credible and reliable. She con-
        cluded Pasano provided reasonable explanations as to why he
        made the decisions he did at trial, based on the dynamics of the trial
        and the factors present at that time.
               After reviewing the witnesses’ testimony from the eviden-
        tiary hearing and making credibility determinations, the magistrate
        judge found that Kallen-Zury had not satisfied either prong of the
        test for ineffective assistance of counsel under Strickland v. Wash-
        ington, 466 U.S. 668, 687 (1984). As to the first prong, i.e., deficient
        performance, none of Pasano’s decisions on the presentation of
        witnesses and documents were of the kind that no competent
        counsel would have taken. This was especially true given the
        strong presumption that his actions fell within the wide range of
        reasonable conduct given his “ample prior trial experience.” Mov-
        ing to the second prong—prejudice—the magistrate judge found
        that there was no reasonable probability that Kallen-Zury’s trial
        would have had a different outcome had Pasano introduced those
        witnesses or documents, and therefore Kallen-Zury could not
        show prejudice. The magistrate judge reviewed his or her credibil-
        ity determinations to conclude that the witnesses were either cred-
        ible, but without valuable testimony, or not credible and incon-
        sistent. Because Kallen-Zury could not satisfy either prong of
        Strickland, the magistrate judge recommended denying the mo-
        tion to vacate.
USCA11 Case: 20-12385      Document: 70-1         Date Filed: 01/12/2023   Page: 14 of 23

        14                      Opinion of the Court                  20-12385

                On April 30, 2020, the district court, after reviewing the rec-
        ord, adopted the magistrate judge’s report and recommendation.
        The district court then issued a certificate of appealability “as to
        [Kallen-Zury’s] claim that her former trial counsel was ineffective
        for failing to call any witnesses at trial other than [Kallen-Zury] her-
        self.”
              Now, in her fourth appeal to this Court regarding her trial,
        Kallen-Zury contends that the district court erred in denying her
        motion to vacate under § 2255.
                         II.    STANDARD OF REVIEW
                In a § 2255 proceeding, we review the district court’s legal
        conclusions de novo and the underlying factual findings for clear
        error. Lynn v. United States, 365 F.3d 1225, 1232 (11th Cir. 2004)
        (citation omitted). “We allot ‘substantial deference to the fact-
        finder . . . in reaching credibility determinations with respect to
        witness testimony.’” Devine v. United States, 520 F.3d 1286, 1287
        (11th Cir. 2008) (quoting United States v. McPhee, 336 F.3d 1269,
        1275 (11th Cir. 2003)).
                                    III.     ANALYSIS
                               A.          Scope of Appeal
               Before getting to the merits of the case, there are two related
        procedural issues we must address. On appeal, Kallen-Zury argues
        that Pasano was ineffective for three reasons: (1) for failing to in-
        troduce various documents, (2) for artificially limiting Dr. Dan-
        ziger’s potential testimony due to counsel’s Federal Rule of
USCA11 Case: 20-12385        Document: 70-1         Date Filed: 01/12/2023        Page: 15 of 23

        20-12385                   Opinion of the Court                              15

        Criminal Procedure 16 violation 4 and decision to limit the sample
        size of Dr. Danziger’s review to nineteen patients, and (3) for fail-
        ing to get Kallen-Zury’s informed consent before deciding not to
        call various witnesses at trial. Unfortunately for Kallen-Zury, the
        first two issues are outside the certificate of appealability, and the
        third issue has been waived because she failed to raise it before the
        district court.
                “[I]n an appeal brought by an unsuccessful habeas peti-
        tioner, appellate review is limited to the issues specified in the [cer-
        tificate of appealability].” Turner v. Sec’y, Dep’t of Corr., 991 F.3d
        1208, 1211 n.1 (11th Cir. 2021) (quoting Murray v. United States,
        145 F.3d 1249, 1250–51 (11th Cir. 1998)). The certificate of appeal-
        ability allowed Kallen-Zury to appeal her claim “that her former
        trial counsel was ineffective for failing to call any witnesses at trial
        other than [Kallen-Zury] herself.” The district court expressly lim-
        ited the scope of the certificate of appealability to the issue of wit-
        nesses, not documents. Therefore, we will not consider Kallen-
        Zury’s arguments about Pasano’s failure to introduce various doc-
        uments at the trial or his decisions affecting the scope of Dr. Dan-
        ziger’s testimony.

        4 At trial, the government made a Rule 16 objection to the use of the charts
        that Dr. Danziger had reviewed, arguing that Pasano failed to disclose them.
        This objection came after Kallen-Zury rested her case and after Pasano de-
        cided not to call Dr. Danziger. The district court ultimately excluded a portion
        of Dr. Danziger’s testimony if Kallen-Zury’s co-defendant called him to testify.
USCA11 Case: 20-12385      Document: 70-1       Date Filed: 01/12/2023      Page: 16 of 23

        16                         Opinion of the Court                20-12385

               Though the argument was not included in the § 2255 mo-
        tion, on appeal, Kallen-Zury argues that once she and counsel
        agreed they would present exculpatory witnesses, counsel needed
        her informed consent not to call them. She claims that counsel’s
        performance was deficient for failing to get such consent. This ar-
        gument might require us to decide as a matter of first impression
        whether the decision to call witnesses at trial belongs to the lawyer
        or the client. But “we have repeatedly held that ‘an issue not raised
        in the district court and raised for the first time in an appeal will not
        be considered by this court.’” Walker v. Jones, 10 F.3d 1569, 1572
        (11th Cir. 1994) (citation omitted). For this reason, we will not con-
        sider Kallen-Zury’s arguments about Pasano’s failure to get her in-
        formed consent not to call any fact witnesses other than Kallen-
        Zury herself.
               With these procedural issues resolved, we turn to the merits
        of Kallen-Zury’s ineffective assistance claim.
                              B.       Strickland Analysis
               To prevail on an ineffective assistance of counsel claim, a pe-
        titioner must “demonstrate both that (1) ‘counsel’s performance
        was deficient,’ and (2) ‘the deficient performance prejudiced the de-
        fense.’” United States v. Webb, 655 F.3d 1238, 1258 (11th Cir. 2011)
        (quoting Strickland, 466 U.S. at 687). “We may consider the prongs
        of the Strickland test in either order, and the defendant must show
        that both prongs are satisfied in order to demonstrate a Sixth
        Amendment violation.” Id. (citation omitted). This standard is
        necessarily a fact-intensive one, requiring a court to “consider[] all
USCA11 Case: 20-12385     Document: 70-1      Date Filed: 01/12/2023     Page: 17 of 23

        20-12385               Opinion of the Court                        17

        the circumstances” when evaluating counsel’s performance.
        Strickland, 466 U.S. at 688. If a defendant makes an insufficient
        showing on one of the requisite prongs, we need not address the
        other prong. Id. at 697; Dingle v. Sec’y for Dep’t of Corr., 480 F.3d
        1092, 1100 (11th Cir. 2007) (citation omitted).
                To establish prejudice under the second prong of Strickland,
        a defendant must show “a reasonable probability that, but for coun-
        sel’s unprofessional errors, the result of the proceeding would have
        been different.” Strickland, 466 U.S. at 694. “A reasonable proba-
        bility is a probability sufficient to undermine confidence in the out-
        come.” Id. In other words, “[i]t is not enough for the defendant to
        show that the errors had some conceivable effect on the outcome
        of the proceeding.” Id. at 693. The petitioner must show instead
        that counsel’s deficient representation rendered the result of the
        trial unfair. See id. at 697. The prejudice component of the Strick-
        land standard thus reflects “[t]he purpose of the Sixth Amendment
        guarantee of counsel,” which is to “ensure that a defendant has the
        assistance necessary to justify reliance on the outcome of the pro-
        ceeding.” Id. at 691–92. This Court has recognized that, given the
        principles and presumptions associated with ineffective assistance
        claims, “the cases in which habeas petitioners can properly prevail
        are few and far between.” Chandler v. United States, 218 F.3d 1305,
        1313 (11th Cir. 2000) (ellipsis omitted) (quoting Waters v. Thomas,
        46 F.3d 1506, 1511 (11th Cir. 1995) (en banc)).
               Strickland prejudice presents a mixed question of law and
        fact, making our review plenary. See, e.g., Brooks v. Comm’r, Ala.
USCA11 Case: 20-12385       Document: 70-1        Date Filed: 01/12/2023        Page: 18 of 23

        18                        Opinion of the Court                    20-12385

        Dep’t of Corr., 719 F.3d 1292, 1300 (11th Cir. 2013). Underlying
        factual determinations, however, are subject to clear error review.
        See Devine, 520 F.3d at 1287.
               Here, we conclude that the district court did not err in de-
        termining Kallen-Zury did not suffer prejudice. The district court
        found that her proposed witnesses were either credible but could
        not offer valuable testimony, or were not credible, and so their tes-
        timony would not have changed the outcome of the trial. We also
        conclude that the magistrate judge’s thorough factual findings set
        forth in the report and recommendation, which were adopted by
        the district court, are not clearly erroneous, especially given the
        substantial deference we afford to the factfinder as to credibility de-
        terminations. See Devine, 520 F.3d at 1287. We briefly discuss
        each proposed witness in turn. 5
               Wagie, although credible according to the magistrate judge,
        was not at HP during the key period in this case, had no knowledge
        of HP’s accounting or marketing operations, and exhibited bias in
        favor Kallen-Zury. The combination of her lack of first-hand
        knowledge and exhibited bias led the magistrate judge to discount
        her potential testimony. Given her lack of firsthand knowledge on
        the critical issues of the case and her bias, it was not error to find

        5
          Because we conclude that Kallen-Zury did not establish prejudice under
        Strickland, we need not determine whether the district court correctly deter-
        mined that her counsel did not exhibit deficient performance. See Strickland,
        466 U.S. at 697.
USCA11 Case: 20-12385     Document: 70-1     Date Filed: 01/12/2023    Page: 19 of 23

        20-12385               Opinion of the Court                      19

        that Wagie’s testimony would not have resulted in a different out-
        come at trial.
               Davidson, while credible in the eyes of the magistrate judge,
        would not have provided valuable testimony, as the financial chart
        he would testify about was introduced by Pasano to avoid the risks
        of cross-examination. The only other testimony Davidson had to
        offer was his statement that the money Kallen-Zury received came
        from sources other than HP. But Davidson admitted at the eviden-
        tiary hearing that all the payments made to Kallen-Zury came from
        HP’s bank account, not the nursing home’s account or any other
        account. Regardless of how money was moving in the back-
        ground, the money paid to Kallen-Zury came from HP. Thus, it
        was not error to conclude that this testimony would not have
        changed the outcome of the trial.
               The magistrate judge determined that Rosier was not credi-
        ble, as she tried to justify the practice of signing blank treatment
        forms after saying such practices were unacceptable. During her
        cross-examination at the evidentiary hearing, she stated that doc-
        tors should not sign blank treatment forms. But when she was pre-
        sented with three separate documented instances of this happening
        at HP, she came up with implausible excuses for each example,
        such as the doctor probably knew the treatment in his head, even
        though she had no knowledge of the specific doctor in that case.
        Her lack of credibility would not have persuaded a reasonable jury.
               Danzig seemed mostly interested in justifying his handling
        of the government subpoena, and so the magistrate judge found
USCA11 Case: 20-12385      Document: 70-1      Date Filed: 01/12/2023     Page: 20 of 23

        20                      Opinion of the Court                 20-12385

        his testimony was colored by self-interest. Given this, the magis-
        trate concluded that his testimony was not valuable. Even if the
        jury determined Danzig were not testifying out of self-interest, all
        he would have told the jury was that Kallen-Zury used lawyers at
        Danzig’s firm to comply with the government subpoena. But the
        jury knew this information already, as the government presented
        documents showing the law firm’s involvement, Kallen-Zury also
        testified to that fact, and Pasano reiterated this during closing argu-
        ments. Therefore, Danzig’s testimony would have been cumula-
        tive and would not contradict the facts underlying Kallen-Zury’s
        crimes.
                As for Hunter, we already concluded, in Kallen-Zury II, that
        neither his testimony about Kallen-Zury’s role with respect to the
        patient register—nor his testimony contradicting Gloria Him-
        mons’s trial testimony—would’ve impacted the outcome of
        Kallen-Zury’s trial. 710 F. App’x at 370–73. What’s more, the mag-
        istrate judge found his testimony at the evidentiary hearing to be
        inconsistent and lacking in credibility. Hunter’s claim that he
        would have testified at Kallen-Zury’s trial was contradicted by the
        fact he invoked his Fifth Amendment rights before the grand jury.
        Additionally, the magistrate judge believed Hunter “had an obvi-
        ous axe to grind against the government after having been prose-
        cuted and acquitted in a parallel case,” further reducing his credi-
        bility. Hunter was uncooperative and contradictory in his cross-
        examination during the evidentiary hearing. For instance, he de-
        nied that Himmons, a recruiter for HP, actually sent patients to
USCA11 Case: 20-12385     Document: 70-1      Date Filed: 01/12/2023     Page: 21 of 23

        20-12385               Opinion of the Court                        21

        HP, but admitted she was a referral source. Then, after admitting
        he did not work with Dr. Gumer—a former HP doctor and gov-
        ernment witness—or know what Dr. Gumer did with patients,
        Hunter said that Dr. Gumer was lying when he admitted to falsify-
        ing patient records at trial. When shown multiple duplicate in-
        voices submitted to or by HP, Hunter claimed the records did not
        seem odd to him. Hunter was also unconcerned over a letter he
        was shown from a doctor at HP that outlined three practices the
        doctor thought were illegal, because according to Hunter, that was
        just what the doctor believed. Hunter admitted on cross-examina-
        tion that HP tracked referrals “indirectly” but claimed this tracking
        was “not really” important. He later contradicted himself by ad-
        mitting that the tracking was important to HP. We thus conclude
        that the district court’s ruling as to this witness was not erroneous.
               As to Dr. Danzinger, his testimony, although found to be
        credible, was of little value according to the magistrate judge, given
        that he analyzed only nineteen of the thousands of patients at HP
        during the period in question. Additionally, his analysis assumed
        the veracity of the treatment forms, even though he had no cor-
        roboration for such an assumption. Given this limited sample size,
        and the fact that the key issue in the case came down to Kallen-
        Zury’s credibility with the jury, there is no reasonable probability
        that Dr. Danziger’s testimony would have led to a different out-
        come.
               The testimony from these witnesses—taken together or sep-
        arately—would not have created a reasonable probability that
USCA11 Case: 20-12385     Document: 70-1      Date Filed: 01/12/2023     Page: 22 of 23

        22                     Opinion of the Court                 20-12385

        Kallen-Zury’s trial would have resulted in a different outcome—
        especially given the deferential standard we afford to credibility de-
        terminations of witnesses by the factfinder, in this case the magis-
        trate judge. See McPhee, 336 F.3d at 1275 (“[W]e allot substantial
        deference to the factfinder . . . in reaching credibility determina-
        tions with respect to witness testimony.” (quoting EEOC v. Joe’s
        Stone Crab, Inc., 220 F.3d 1263, 1285–86 (11th Cir. 2000))). The
        magistrate judge conducted three full days of evidentiary hearings,
        listening to the testimony that each proposed witness would have
        given at Kallen-Zury’s trial. The magistrate judge made certain
        credibility determinations that were reasonable based on our re-
        view of the transcripts, and we will not second guess those deter-
        minations here. Based on those determinations, the magistrate
        judge found that the proposed witnesses would not have changed
        the outcome of the trial. The district court adopted those findings
        and conclusions, and we cannot conclude that this was error.
               Kallen-Zury’s proposed witnesses would have been of lim-
        ited value to her defense, especially considering the weight of evi-
        dence against her presented during the five-week trial. At a trial
        where the key issue became her credibility, Kallen-Zury’s testi-
        mony contradicted the testimony of several government witnesses
        on a number of points. There were several discrepancies between
        Kallen-Zury’s testimony and the testimony of other witnesses (in-
        cluding three patient recruiters and two of Kallen-Zury’s own em-
        ployees), which were sufficient to damage her credibility in the ju-
        rors’ eyes. And so, she cannot show that she was prejudiced by
USCA11 Case: 20-12385     Document: 70-1      Date Filed: 01/12/2023     Page: 23 of 23

        20-12385               Opinion of the Court                        23

        Pasano’s failure to call these witnesses at trial and therefore cannot
        satisfy the second Strickland prong. See Strickland, 466 U.S. at 694.
        Thus, her ineffective assistance of counsel claim must fail.
                               IV.    CONCLUSION
               For all these reasons, we conclude that the district court did
        not err in concluding that the testimony of the proposed witnesses
        would not have changed the outcome of the trial. As a result,
        Kallen-Zury was not prejudiced by her counsel’s decision not to
        call those witnesses at trial. We therefore affirm the denial of her
        § 2255 motion.
              AFFIRMED.