What is the test for probable cause in civil cases?

"[P]robable cause requires only a probability or substantial chance of criminal activity, not an actual showing of such activity." Illinois v. Gates, 462 U.S. 213, 245 n.13 (1983). "[W]e review for clear error the factual findings that underpin a district court's assessment of probable cause, but we review de novo whether a set of facts satisfies the probable cause standard." United States v. Rajaratnam, 719 F.3d 139, 153 (2d Cir. 2013) (internal quotation marks omitted).

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