The "Door-Knocker" was Ford Explorer owned by the San Atanasio Police Department which they had heavily modified. It had been armored against small-arms fire but retained vision and firing slits for the occupants. It also had a ram installed in front of the hood for smashing down barricaded entryways. The intention was to have an armored car to safely break into crack houses, meth labs and the like.
When Chief Mike Pitcavage asked Lt. Colin Ferguson to coordinate security for a shipment of crude oil coming by tanker to San Pedro for trans-shipment to refineries in El Segundo, Ferguson asked for and received permission to use the Door-Knocker. While there was some concern over street gangs high-jacking the shipment, the main reason was the shipment was intended for South Bay Police Departments and might be diverted by the Los Angeles P.D.
On the day of the shipment, Lt. Ferguson along with select officers were waiting at the Braxton Bragg Blvd. overpass to the Harbor Freeway. He had the Door-Knocker ready with it mounting a full size machine gun he had found in the armory. In addition, his officers were all issued M16 rifles with full auto-fire select. Despite Chief Pitcavage's assurances that "necessary arrangements" had been made to keep the shipment secret, LAPD cruisers showed up on the segment of the highway within L.A. jurisdiction to try to block and divert the shipment. Lt. Ferguson intervened and the threat posed by the Door-Knocker and heavily armed officers succeeded in making the LAPD back down without any shots being fired.
With the Door-Knocker leading the parade, Lt. Ferguson along with a number of San Atanasio Police cruisers escorted the crude oil tanker trucks to the Hawthorne boundary and handed them over to that P.D.