MEMORANDUM *
Correctional officers and their supervisors appeal from the district court’s order denying them summary judgment on grounds of qualified immunity in Plaintiff Terrance Covington’s action under 42 U.S.C. § 1983. Plaintiff alleged that the officers used excessive force, in violation of the Eighth Amendment, during a “cell extraction” and that the supervisors witnessed that violation but failed to stop it.
1. Saucier Step One
Considering all the materials submitted in support of, and in opposition to, summary judgment and resolving all factual disputes in Plaintiffs favor, we conclude that Plaintiffs Eighth Amendment rights were violated. See Jeffers v. Gomez, 267 F.3d 895, 909 (9th Cir.2001) (per curiam) (describing the first step of the qualified immunity test in Saucier v. Katz, 533 U.S. 194, 201, 121 S.Ct. 2151, 150 L.Ed.2d 272 (2001)); Hudson v. McMillian, 503 U.S. 1, 7, 112 S.Ct. 995, 117 L.Ed.2d 156 (1992) (setting forth the standard for evaluating whether a prison security measure involved excessive force in violation of the Eighth Amendment).
In his verified complaint, which we may treat as an opposing affidavit, McElyea v. Babbitt, 833 F.2d 196, 197-98 (9th Cir. 1987) (per curiam), Plaintiff alleged that Defendants Lopez, Haskins, Ballesteros, Barrier, and Davis — all of whom were members of the cell extraction team — hit him in the “body and head” and that Defendant Zinani hit him in the “body and head and penis area.” In his deposition, he testified that, when the officers entered the cell: “[T]hey was just hittin’ me. Hit-tin’ me in my groin, hittin’ me in [my] face, hittin’ me in my body.” He also testified that later, after he was on the ground, the officers continued to hit him, knee him, and step on him. While he was on the ground, Defendant Brown “started to twist my foot until it was almost broken.” As alleged by Plaintiff, the beating was out of proportion to the officers’ legitimate need to end the nonviolent “boarding up” incident and out of proportion to Plaintiffs resistance. If Plaintiffs version of events is believed, the incident amounted to a wanton beating in violation of the Eighth Amendment, even though it did not result in serious, lasting injury. See Hudson, 503 U.S. at 7 (stating that it is proper to consider factors such as “the need for application of force, the relationship between the need and the amount of force used, the threat ‘reasonably perceived by the responsible officials,’ [ ] ‘any efforts made to temper the severity of the forceful response,’ ” and the extent of injury, but holding that serious injury is not required (quoting Whitley v. Albers, 475 U.S. 312, 321, 106 S.Ct. 1078, 89 L.Ed.2d 251 (1986))); Whitley, 475 U.S. at 320 (stating that the infliction of “unnecessary and wanton pain” violates the Eighth Amendment).
Plaintiffs claims against Defendants Mattingly, Quiñones, and Valenzuela proceed on a theory of supervisory liability. A supervisor is liable under § 1983 if there exists “ ‘a sufficient causal connection between the supervisor’s wrongful conduct and the constitutional violation.’ ” Jeffers, 267 F.3d at 915 (quoting Redman v. County of San Diego, 942 F.2d 1435, 1446 (9th Cir.1991)). Specifically, “a prison official can violate a prisoner’s Eighth Amendment rights by failing to intervene” to prevent a constitutional violation. Robins *741v. Meecham, 60 F.3d 1436, 1442 (9th Cir. 1995).
In his complaint, Plaintiff alleged that Defendants Mattingly, Quiñones, and Valenzuela “witness[ed] this brutal beat[ing] but failed to act to stop it.” Furthermore, there is some evidence that Valenzuela knew that certain other defendants should not have participated in the cell extraction. In the light of our conclusion that the alleged beating described above violated the Eighth Amendment (and also in consideration of the evidence of beating by additional defendants who either did not seek qualified immunity or did not appeal its denial), the allegations that the supervisors failed to act establishes supervisory liability under § 1983.
2. Saucier Step Two
It would have been “‘clear to a reasonable officer that his conduct was unlawful in the situation he confronted.’ ” Clement v. Gomez, 298 F.3d 898, 906 (9th Cir.2002) (quoting Saucier, 533 U.S. at 202). Even if Defendants had a “ ‘mistaken understanding as to whether a particular amount of force [was] legal’” in the circumstances, Jeffers, 267 F.3d at 909 (quoting Saucier, 533 U.S. at 205), their mistake would have been unreasonable.
In September 1998, it was clearly established that inmates were protected from wanton beatings that exceeded correctional officers’ good-faith efforts to address a violation of prison rules. See Martinez v. Stanford, 323 F.3d 1178, 1180, 1184 (9th Cir.2003) (holding that, because the law regarding excessive force was clearly established in 1994, that qualified immunity was improperly granted to officers who allegedly beat an inmate during a cell extraction, despite the inmate’s lack of resistance); McRorie v. Shimoda, 795 F.2d 780, 784 (9th Cir.1986) (holding that the Eighth Amendment was violated by an assault while an inmate was not resisting). Moreover, it was clearly established that significant injury is not required to make out an Eighth Amendment violation. See Hudson, 503 U.S. at 7 (stating that “[t]he absence of serious injury is ... relevant to the Eighth Amendment inquiry, but does not end it”). It was also clearly established that supervisors could be hable for failing to stop constitutional violations. Robins, 60 F.3d at 1442.
3. Internal Investigative Reports
Defendants’ assertion that the redacted investigative reports should not be considered must fail. Insofar as Defendants raise a claim of error by the district court in granting the motion to compel or in accepting and relying on the materials, their claim was not stated in the opening briefs and therefore need not be considered. Insofar as Defendants claim that we can review only what is in the parties’ excerpts of record, as distinct from the entire actual record, they are simply mistaken; the whole record is before us on de novo review. See Johnson v. County of Los Angeles, 340 F.3d 787, 791 (9th Cir. 2003) (reviewing de novo the denial of a motion for summary judgment based on qualified immunity).
AFFIRMED.
This disposition is not appropriate for publication and may not be cited to or by the courts of this circuit except as may be provided by Ninth Circuit Rule 36-3.