As there was no particular and objective basis for the Terry stop and the arrest of the foreign national was effectuated by handcuffing and placing into the patrol car prior to the contact with federal immigration authorities that gave probable cause for the arrest, S1983 suit against the officer states a claim.
As the actions of the Justice of the Police who called the officer to the courtroom upon leaning from a testifying witness that the plaintiff was in the country illegally were both a but/for cause and a proximate cause of the deprivation of 4A, the JP was a sufficiently integral participant for the purposes of a S1983 claim.
Circuit caselaw was clearly established at time, holding that lack of documentation or other admission of illegal presence was insufficient probable cause for an arrest for illegal entry.