Officer Leon Lopez says the Monday afternoon tow-away proved difficult because the bus's brakes wouldn't release.
The bus carrying a group from Tijuana, Mexico, to the San Bernardino Mountains east of Los Angeles collided with a car and a pickup Sunday night. Debris and body parts created a scene of horrific carnage.
The other vehicles will also be towed.
The bus could not be entered until Monday because the wreckage was precariously hanging off the road.
Dozens of people were injured, some critically.
A hazardous materials team is cleaning the road of fuel and any biohazards from the accident.