Prisons, FTCA.
As the decision to separate certain prisoners from each other is discretionary, yet implicates considerations of public policy, suit against officials is barred under FTCA.
Claims of inadequate or omitted searches of assailants should be remanded for discovery, as they implicate claims outside of the discretionary exception.
http://www.ca4.uscourts.gov/Opinions/Published/147204.P.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.