D.C. Circuit
Polk v. District of Columbia, 121 F. Supp. 2d 56, 70-71 (D.D.C. 2000) (holding that, where police officer allegedly directed ride-along civilian to detain someone for whom there was no probable cause, the absence of any reported cases addressing that precise conduct did not foreclose a determination that the right to be free from such detentions was clearly established; there was no “open question” whether the Constitution outlawed the officer’s conduct and “there can be little doubt that the Constitution forbids police officers to share their authority to conduct searches and seizures with unauthorized civilians”).
Second Circuit
Simon v. City of New York, 893 F.3d 83, 88 (2d Cir. 2018) (“No officer who is executing a warrant that requires that a prospective material witness be brought before a judge at a fixed date and time to determine whether the witness should be detained can reasonably believe that she is free instead to detain and interrogate the witness for hours on end outside of court supervision.”).