The opinion of the court was delivered by: Ricardo M. Urbina United States District Judge
GRANTING THE DEFENDANTS'MOTION TO DISMISS
This matter is before the court on the defendants' motion to dismiss the plaintiff's amended complaint. The plaintiff brings this action on behalf of the estate of an individual who committed suicide while in the custody of the District of Columbia Metropolitan Police Department ("MPD"). The plaintiff has asserted § 1983 claims against the District of Columbia ("the District") and MPD Chief Cathy Lanier based on alleged violations of the decedent's Fifth and Eighth Amendment rights, as well as common law claims against these defendants for wrongful death and negligence. The defendants assert that the plaintiff has failed to state a § 1983 claim against them because the plaintiff has not adequately alleged that the District or Chief Lanier acted with deliberate indifference to the decedent's constitutional rights. The defendants further contend that absent these § 1983 claims, the court should decline to exercise pendent jurisdiction over the plaintiff's remaining state law claims. For the reasons discussed below, the court grants the defendants' motion, dismissing certain claims with prejudice and other claims without prejudice.
II. FACTUAL & PROCEDURAL BACKGROUND*fn1
On May 5, 2008, Shantee Parker ("the decedent") was arrested and taken to the MPD's Fourth District Precinct. Am. Compl. ¶ 6. While in custody, the decedent was placed alone in a cell without a working camera where she committed suicide by hanging herself. Id. ¶ 12. The plaintiff alleges that even though the decedent "exhibited many signs of distress, disorientation and confusion" at the time she was brought into custody, "none of the personnel at the 4th Precinct properly monitored [the] decedent or assured that she was not placed in an environment where instruments that could be used in a suicide attempt were  available." Id. ¶ 8. The plaintiff also alleges that "the defendants had previously encountered [the] decedent and were well aware of the decedent's mental health frailties, including suicidal tendencies, long before May 5, 2008." Id. ¶ 6.
The plaintiff commenced this action on behalf of the decedent's estate in the Superior Court for the District of Columbia. See generally Compl. On June 29, 2009, the defendants removed the case to this court, and on September 8, 2009, the plaintiff filed an amended complaint. See generally id.; Am. Compl. In the amended complaint, the plaintiff asserts claims against the District and against Chief Lanier in her official and individual capacities. Am. Compl. ¶¶ 4-5. The plaintiff asserts that the defendants deprived the decedent of her Fifth and Eighth Amendment rights, in violation of 42 U.S.C. § 1983, by failing to provide detainees like the decedent with necessary protection and treatment and by failing to properly train and supervise MPD personnel. Id. ¶¶ 23-32. In addition, the plaintiff asserts common law wrongful death and negligence claims against the defendants. Id. ¶¶ 18-22, 33-36. On September 18, 2009, the defendants filed this motion to dismiss the amended complaint. See generally Defs.' Mot. to Dismiss. The defendants contend that the amended complaint fails to state a claim for relief under § 1983, and that without those claims, the court lacks an independent basis for exercising jurisdiction over the remaining common law claims. Id. at 1-2. With the defendants' motion now ripe for adjudication, the court turns to the applicable legal standards and the parties' arguments.
A. The Court Dismisses the Plaintiff's § 1983 Claims Under Rule 12(b)(6)
1. Legal Standard for Dismissal Under Federal Rule of Civil Procedure 12(b)(6)
A Rule 12(b)(6) motion to dismiss tests the legal sufficiency of a complaint. Browning v. Clinton, 292 F.3d 235, 242 (D.C. Cir. 2002). The complaint need only set forth a short and plain statement of the claim, giving the defendant fair notice of the claim and the grounds upon which it rests. Kingman Park Civic Ass'n v. Williams, 348 F.3d 1033, 1040 (D.C. Cir. 2003) (citing FED. R. CIV. P. 8(a)(2) and Conley v. Gibson, 355 U.S. 41, 47 (1957)). "Such simplified notice pleading is made possible by the liberal opportunity for discovery and the other pretrial procedures established by the Rules to disclose more precisely the basis of both claim and defense to define more narrowly the disputed facts and issues." Conley, 355 U.S. at 47-48 (internal quotation marks omitted). It is not necessary for the plaintiff to plead all elements of his prima facie case in the complaint, Swierkiewicz v. Sorema N.A., 534 U.S. 506, 511-14 (2002), or "plead law or match facts to every element of a legal theory," Krieger v. Fadely, 211 F.3d 134, 136 (D.C. Cir. 2000) (internal quotation marks and citation omitted).
Yet, "[t]o survive a motion to dismiss, a complaint must contain sufficient factual matter, accepted as true, to state a claim to relief that is plausible on its face." Ashcroft v. Iqbal, 129 S.Ct. 1937, 1949 (2009) (internal quotation marks omitted); Bell Atl. Corp. v. Twombly, 550 U.S. 544, 562 (2007) (abrogating the oft-quoted language from Conley, 355 U.S. at 45-46, instructing courts not to dismiss for failure to state a claim unless it appears beyond doubt that "no set of facts in support of his claim [ ] would entitle him to relief"). A claim is facially plausible when the pleaded factual content "allows the court to draw the reasonable inference that the defendant is liable for the misconduct alleged." Iqbal, 129 S.Ct. at 1949 (citing Twombly, 550 U.S. at 556). "The plausibility standard is not akin to a 'probability requirement,' but it asks for more than a sheer possibility that a defendant has acted unlawfully." Id. (citing Twombly, 550 U.S. at 556).
In resolving a Rule 12(b)(6) motion, the court must treat the complaint's factual allegations -- including mixed questions of law and fact -- as true and draw all reasonable inferences therefrom in the plaintiff's favor. Holy Land Found. for Relief & Dev. v. Ashcroft, 333 F.3d 156, 165 (D.C. Cir. 2003); Browning, 292 F.3d at 242. While many well-pleaded complaints are conclusory, the court need not accept as true inferences unsupported by facts set out in the complaint or legal conclusions cast as factual allegations. Warren v. Dist. of Columbia, 353 F.3d 36, 39 (D.C. Cir. 2004); Browning, 292 F.3d at 242. "Threadbare ...