Under what circumstances will a prison official be found guilty of failing to protect an inmate from attacks by other inmates?

Under the Eighth Amendment, prison officials must take reasonable measures to guarantee the safety of inmates. Farmer v. Brennan, 511 U.S. 825, 832 (1994). Prison officials have an affirmative duty to protect prisoners from violence at the hands of other prisoners. Id. at 832. A prison official's failure to protect an inmate from attacks by other inmates violates the Eighth Amendment only when two elements are met: (1) the objective element, which requires a prisoner to show that the complained of conditions posed a "substantial risk of serious harm," and (2) the subjective element, which requires a prisoner to show that the defendant was deliberately indifferent to that risk. Id. at 834.