Three people have been taken into custody after a dramatic arrest on the Narrows Bridge on Tuesday afternoon.
It is understood authorities pulled over a car after a police number plate scanner had issued an alert for the Hyundai.
Officers reduced traffic to just one lane as they intercepted the vehicle.
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At least one more police car was called for backup and three people were taken into custody for questioning.
It is understood one of them was wanted by WA Police.
Vision captured by 7NEWS showed items being seized by police from the car at the nearby Fraser Lane in South Perth.