The Ninth Circuit has held that an applicant for withholding of removal need not prove that a protected ground (i.e. his political opinion, religion, membership in a particular social group, etc.) is one central reason for the persecution inflicted on him. The court noted that when Congress amended the asylum statute to include the "one central reason" requirement, it did not similarly amend the withholding of removal statute. Thus, an applicant for withholding of removal need only show that a protected ground is "a reason" for the harm inflicted on him, and not "one central reason." In so holding, the Ninth Circuit rejected the Board of Immigration Appeals' decision in Matter of C-T-L-, which extended the one central reason standard to withholding of removal.
With respect to the petitioner's application for protection under the Convention Against Torture, the Court noted that there is no "rogue official" exception to this protection. "Since the officers were apparently off duty when they tortured Barajas-Romero, they were evidently not acting 'in an official capacity,' but the regulation does not require that the public official be carrying out his official duties, so long as he is the actor or knowingly acquiesces in the acts."
The full text of Barajas-Romero v. Lynch can be found here:
http://cdn.ca9.uscourts.gov/datastore/opinions/2017/01/18/13-70520.pdf