(CNN) Armando Colunga was watching the news in San Antonio when he saw a report Tuesday night about authorities discovering 54 undocumented immigrants in the back of an 18-wheeler truck.

The men were being detained, sitting in a group on the ground, while they waited for authorities to interview and transport them.

Colunga felt compelled to act. The tow truck driver hopped in his vehicle and drove across town to help.

"My main motivation was, 'Who knows how long they've been in there?'" he said.

When Colunga got to the scene, he noticed a Little Caesars nearby and bought seven pizzas.

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