Never—never, mention citizen’s arrest to a cop.
Nothing riles a cop up like having the citizenry do their job for them. They immediately think Vigilante’s and realise that if Vigilantes do their job, they won’t be needed.
They go pschycho, when a citizen does their job.
Most of them go psycho if you just ask a simple question of them, or God forbid you question their justification about any of their actions...