*1 Before the Court are four motions in limine filed by Defendant Hilton Hotels Corporation, specifically: Defendant's Motion in Limine to Exclude Witnesses Not Identified in Discovery (Dkt. No. 42.); Defendant's Motion in Limine to Exclude Exhibits Not Disclosed During Discovery (Dkt. No. 43.); Defendant's Motion in Limine to Exclude Confusing, Misleading, and Unfairly Prejudicial Testimony (Dkt. No. 44.); and Defendant's Motion in Limine to Exclude Testimony Regarding Non-Tortious or Unreported Activity. (Dkt. No. 45.). Having considered the parties’ arguments, the record of the case, and relevant case law, the Court finds and rules as follows.

This case arises out of a dispute between Plaintiff Mesafint Beyene (“Plaintiff”), who has worked as a room service waiter at the Washington, D.C. Hilton since 1999, and his employer, Defendant Hilton Hotels Corporation (“Defendant”). According to Plaintiff, he began feeling threatened and harassed at work after he reported two of his co-workers, Jaman Chowdhury and Yazan Saleh to the U.S. Secret Service, the Federal Bureau of Investigations, and Defendant's security department after overhearing them make threats against then-President Bush. Beyene v. Hilton Hotels Corp., 815 F. Supp. 2d. 235, 239-40 (D.D.C. 2011) In his Amended Complaint, Plaintiff alleges employment discrimination, intentional infliction of emotional distress, negligent hiring, negligent retention, and invasion of privacy. Am. Compl. (Dkt. No. 18.). The Court granted summary judgment as to all but the negligent retention claim. Beyene, 815 F. Supp. 2d. at 254. In this remaining count, Plaintiff alleges that Defendant negligently allowed Chowdhury and Saleh, to continue working alongside Plaintiff, despite Plaintiff reporting to Defendant that these employees had threatened him with violence.[1]

1) Defendant's Motion in Limine to Exclude Witnesses Not Identified in Discovery

Defendant argues that, pursuant to Rule 37(c)(1), any witnesses Plaintiff has not disclosed during the discovery period should be excluded from trial. (Dkt. No. 42 at 1-2.). Federal Rule of Evidence 37(c) provides that “[i]f a party fails to ... identify a witness as required by Rule 26(a) or (e), the party is not allowed to use that ... witness ... at trial, unless the failure was substantially justified or is harmless.” Defendant argues Plaintiff failed to make any initial disclosures, as required by Rule 26(a), though he did subsequently identify 23 potential witnesses during the course of discovery. (Dkt. No. 42 at 2-3.). Defendant seeks only to exclude witnesses who have never been identified or only vaguely referenced during depositions. Id. at 3. Plaintiff has not filed any opposition to Defendant's motion.

Under Local Civil Rule 7(b), if a party fails to file a memorandum of points and authorities in opposition to a motion, “the Court may treat the motion as conceded.” “[T]he discretion to enforce [Rule 7(b)] lies wholly with the district court: ‘Where the district court relies on the absence of a response as a basis for treating the motion as conceded, [the D.C. Circuit] honor[s the district court's] enforcement of the rule.’ ” FDIC v. Bender, 127 F.3d 58, 68 (D.C. Cir. 1997) (quoting Twelve John Does v. District of Columbia, 117 F.3d 571, 557 (D.C. Cir. 1997). Given Plaintiff's failure to file an opposition, the Court finds Defendant's motion conceded. Alternatively, the Court finds merit to Defendant's substantive argument. “Under Rule 37, the sanction of exclusion of a witness is automatic and mandatory unless the party to be sanctioned can show that its violation was either substantially justified or harmless.” Elion v. Jackson, 544 F. Supp. 2d 1, 6 (D.D.C. 2008) (internal citation omitted). Plaintiff, having entirely failed to oppose Defendant's motion, has made no such showing. Thus, Defendant's motion is granted, and Plaintiff is precluded from calling witnesses not previously disclosed or clearly identified over the course of discovery.

2) Defendant's Motion in Limine to Exclude Exhibits Not Disclosed During Discovery

*2 Defendant argues that, pursuant to Rule 37(c)(1), the Court should exclude from trial any exhibits not disclosed during discovery. (Dkt. No. 43 at 1.). As with witnesses, Rule 37(c)(1) provides for the exclusion of documents not disclosed as required under Rule 26(a) and (e) unless the failure was substantially justified or is harmless. Fed. R. Evid. 37(c)(1). Defendant argues that Plaintiff failed to provide any initial disclosure under Rule 26(a). (Dkt. No. 43 at 2.) Defendant acknowledges that, over the course of discovery, Plaintiff provided Defendant with a limited amount of documents including a number of medical records. Id.. Plaintiff argues that he should be permitted to use documents previously disclosed, including the medical records. Pl.’s Opp'n (Dkt. No. 47 at 2.). Defendant clarifies that it seeks to exclude only those documents that were never disclosed during the two lengthy discovery periods of the case. Def.’s Reply (Dkt. No. 50 at 1.).

“It is understood in this Circuit that when a plaintiff files an opposition to a ... motion and addresses only certain arguments raised by the defendant, a court may treat those arguments that the plaintiff failed to address as conceded.” Buggs v. Powell, 293 F. Supp. 2d 135, 141 (D.D.C. 2003); accord Kone v. District of Columbia, 808 F. Supp. 2d 80, 83 (D.D.C. 2011). Because Plaintiff did not contest that the documents he never disclosed are excludable, the Court finds Defendant's argument conceded. Additionally, the Court finds that Rule 37(c) supports Defendant's arguments. By its plain language, Rule 37(c) excludes evidence not disclosed during discovery, see Thomas v. Paulson, 507 F. Supp. 2d. 59, 80 (D.D.C. 2007), and “the sanction of exclusion is automatic and mandatory,” Elion, 544 F. Supp. 2d at 6 (internal citation omitted). Accordingly, Defendant's motion is granted and Plaintiff is precluded from presenting exhibits not previously disclosed during discovery.

3) Defendant's Motion in Limine to Exclude Confusing, Misleading, and Unfairly Prejudicial Testimony

A) Testimony and Evidence Concerning National Origin and Religion

Plaintiff alleges that, in addition to making threats of physical violence against him, Chowdhury and Saleh harassed him because of his faith and national origin. Defendant argues that testimony and evidence concerning references to national origin and religion should be excluded as irrelevant to the remaining negligent retention claim. According to Defendant, while Chowdhury and Saleh's comments concerning Plaintiff's faith and national origin may have been relevant to Plaintiff's discrimination claims, those claims have been dismissed on summary judgment, leaving only negligent retention. (Dkt. No. 44 at 4.). Plaintiff counters that, because the adequacy of Defendant's investigation of Chowdhury and Saleh's conduct is at issue, whether or not Defendant uncovered their national origin- or religious-based animus towards Plaintiff is relevant to the thoroughness of the investigation. Pl.’s Opp'n (Dkt. No. 49 at 2.).

As discussed in more detail in Part 4 infra, negligent retention must be predicated on either independent tortious conduct by an employee or a breach of a duty imposed on the employer at common law. See Griffin v. Acacia Life Ins. Co., 925 A.2d 564, 576-77 (D.C. 2007). Plaintiff has stated that his negligent retention claim rests on the independent tortious conduct of Chowdhury and Saleh – specifically, the threats of violence made against Plaintiff, allegedly amounting to an assault. (Dkt. No. 48 at 2.). And while Plaintiff now argues that Defendant's investigation was inadequate because it failed to reveal his co-workers’ national origin- and religious-based animus towards him, (Dkt. No. 49 at 2.), Plaintiff has previously conceded that he was assaulted solely as retaliation for a report he lodged against Chowdhury and Saleh concerning threats they made against then-President George W. Bush, see Beyene, 815 F. Supp. 2d at 247. Accordingly, the Court finds that any testimony or evidence concerning national origin or religion is not relevant to the negligent retention claims and must be excluded. See Fed. R. Evid. 401.

*3 Furthermore, Defendant points out that references to national origin and religion should be excluded under Federal Rule of Evidence 403. (Dkt. No. 44 at 5.) As Defendant suggests, reference to Plaintiff's harassment on account of his religion and national origin have little probative value and the likelihood that such evidence would be extraneous, confusing, and potentially inflammatory is high. Id. Plaintiff counters that Defendant has not met its burden, under Rule 403, of establishing that the danger of unfair prejudice substantially outweighs the evidence's probative value. (Dkt. No. 49 at 3.). The Court agrees with Defendant. The issues that remain concern the alleged assault, or assaults, on Plaintiff and the adequacy of Defendant's response. Plaintiff has not argued convincingly that any national origin- or religious-based animus Chowdhury and Saleh may have held toward Plaintiff has any probative value regarding either of these issues. Accordingly, references to national origin and religion must be excluded.

B) Reference to “Injections”

Defendant argues that any reference to “injections” should be prohibited as needlessly confusing. (Dkt. No. 44 at 6.). Hilton employees apparently use the term “injection” as a euphemism to refer to disciplinary action or “write ups” from their employer. Id. Plaintiff counters that the “write ups” in questions are relevant as evidence of Defendant's harassment of Plaintiff. The Court agrees with Defendant. To be clear, the Court does not prohibit reference to relevant disciplinary action generally – only the use of the term “injection,” as this term is likely to confuse or mislead a jury while having little or no probative value. See Fed. R. Evid. 403.

C) Testimony and Evidence Concerning Firing and Rehiring of Chowdhury

Defendant argues that any reference to Hilton's firing and re-hiring of Chowdhury should be excluded as irrelevant. Plaintiff's Amended Complaint alleged that Defendant negligently hired Chowdhury (after firing him for a brief time). However, the Court dismissed Plaintiff's negligent hiring claim on summary judgment because the only evidence supporting Plaintiff's claim was Plaintiff's own inadmissible hearsay. Beyene, 815 F. Supp. 2d at 251-52. Thus, Defendant contends that evidence concerning this matter should be excluded as irrelevant and likely to confuse or mislead the jury. In as much as Plaintiff does not address Defendant's argument in his opposition, the Court finds the point conceded. See Buggs, 293 F. Supp. 2d at 141. Furthermore, as Plaintiff's negligent hiring claim has been dismissed, the Court finds the firing and re-hiring of Chowdhury to be of no “consequence in determining the action,” see Fed. R. Evid. 401, and reference to the matter at trial is precluded.

D) Opinion Testimony and Testimony Beyond Plaintiff's Personal Knowledge

Defendant requests that Plaintiff be formally instructed to avoid giving testimony concerning his personal opinions concerning the adequacy of Defendant's investigation of Chowdhury and Saleh's conduct. (Dkt. No. 44 at 7.). Defendant's concern arises from Plaintiff's deposition testimony in which he “freely mix[ed] in conclusory allegations with his factual testimony.” Id. Federal Rule of Evidence 602 limits a witness's testimony to matters for which he has personal knowledge. Federal Rule of Evidence 701 limits the circumstances in which a lay witness may provide opinion testimony. Plaintiff's counsel is hereby cautioned to inform his client of the proper bounds of testimony, as prescribed by the Federal Rules of Evidence.

4) Defendant's Motion in Limine to Exclude Testimony Regarding Non-Tortious or Unreported Activity

A) Non-Tortious Activity

Defendant argues that any evidence of acts by Chowdhury and Saleh that do not amount to independent tortious conduct should be exclude as irrelevant, unfairly prejudicial, confusing, and misleading to a jury. Defendant's argument is rooted in the law of negligent retention. To establish a claim for negligent retention, a plaintiff must show “that the employer breached a duty to plaintiff to use reasonable care in the ... retention of an employee which proximately caused harm to plaintiff.” Phelan v. City of Mount Rainier, 805 A.2d 930, 940 (D.C. 2002). This theory requires that “an employer knew or should have known its employee behaved in a dangerous or otherwise incompetent manner, and that the employer, armed with that actual or constructive knowledge, failed to adequately supervise the employee.” Brown v. Argenbright Sec., Inc., 782 A.2d 752, 760 (D.C. 2001). Furthermore, negligent retention must be “predicated only on common law causes of action or duties otherwise imposed by the common law .... To hold otherwise would be to impose liability on the employer for failing to prevent a harm that is not a cognizable injury under the common law.” Griffin v. Acacia Life Ins. Co., 925 A.2d 564, 576-77 (D.C. 2007).

*4 Plaintiff claims that the underlying tortious conduct in this case was an assault, or series of assaults, committed against Plaintiff by Chowdhury and Saleh. See Pl.’s Opp'n (Dkt. No. 48 at 2.). As Plaintiff states in his opposition, common law assault consists of “an intentional and unlawful attempt or threat, either by words or by acts, to do physical harm to the victim.” Id. (citing Etheredge v. District of Columbia, 635 A.2d 908, 916 (D.C. 1993). The victim must also be put in “imminent apprehension” of such harm. Jackson v. District of Columbia, 412 A.2d 948, 955 fn. 15 (D.C. 1980) (citing Restatement (Second) of Torts § 21 (1965)). As such, the Court finds that any conduct by Chowdhury and Saleh, that does not amount to attempts or threats to do physical harm to the Plaintiff, such as mere acts of incivility, are not relevant to Plaintiff's negligent retention claim. See Fed. R. Evid. 401 (“Evidence is relevant if (a) it has any tendency to make a fact more or less probable than it would be without the evidence; and (b) the fact is of consequence in determining the action.). Accordingly, evidence concerning non-tortious conduct by Chowdhury and Saleh must be excluded from trial.

B) Unreported Activity

Defendant next argues that any harassing conduct not reported by Plaintiff to Hilton is irrelevant, misleading, and unfairly prejudicial. (Dkt. No. 45 at 3-4.). Defendant contends that the only remaining issue is the adequacy of Defendant's response to Plaintiff's reports of harassment by Chowdhury and Saleh. Id. According to Defendant, its response could not have been negligent if it was not informed of wrong-doing. Id. As explained above, a claim of negligent retention requires a showing that “an employer knew or should have known its employee behaved in a dangerous or otherwise incompetent manner, and that the employer, armed with that actual or constructive knowledge, failed to adequately supervise the employee.” Brown, 782 A.2d at 760. Accordingly, the Court agrees with Defendant that it cannot be held responsible for incidents involving Plaintiff and his co-workers that it was not made aware of. However, whether an incident was reported to Defendant, and the adequacy of Defendant's response are matters for the jury to decide.

For the foregoing reasons, it is hereby ORDERED:

Dated this 13th day of November, 2012.

For a full discussion of the facts of the case, see Beyene v. Hilton Hotels Corp., 815 F. Supp. 2d. 235 (D.D.C. 2011).