"My main motivation was, 'Who knows how long they've been in there?" he told CNN.
When he got back to the scene, two detectives helped him through the yellow tape, where another officer gave the pizzas to a firefighter, who then gave them to the group, according to CNN.
"They were happy they were eating something. I figured they hadn't ate in a while," Colunga told KSAT. "They're not here to commit crime, they're here for a better life, to work. They're harder working people than some of our people here that are citizens."
Homeland Security Investigations agents arrested the illegal immigrants. The driver, who has not been identified, was also arrested and expected to be charged with human smuggling, according to officials.