FORT WORTH, Texas—A truck-driving thief made off with more than $3 million worth of merchandise from a venerable maker of cowboy boots and other footwear, authorities said.

The thefts occurred Labor Day weekend and Nov. 9 at a Justin Boots distribution center, said Fort Worth police Lt. Paul Henderson.

A surveillance video shows a white single-cab tractor entering the property without a trailer and each time leaving with one. The driver gained entry by cutting the locked chain securing the gate, Henderson said.