Gangsters' warnings to migrants not to go to the police are ruthlessly enforced. Julio César Cancino Gálvez, with Grupo Beta Sur, recalls how a group of about thirty migrants at the Tapachula train station asked him why the authorities weren't clamping down on the gangsters. Cancino told them they needed witnesses. He urged the migrants to step forward and report abuses. One nineteen-year-old Honduran in the crowd spoke up. He described his assailant in detail. Hours later, the Red Cross asked Cancino if he could help an injured migrant. It was the same Honduran teenager. His right ribs were broken. His entire chest and face were badly bruised. He spoke slowly, in a whisper, clasping his chest. Two gangsters had overheard his description and kicked him mercilessly. "Next time, we kill you," the gangsters told him. The teenager, afraid for his life, asked to be deported.

—Enrique’s Journey,

Sonia Nazario

The underlined sentences demonstrate characterization. How does this technique support the author’s purpose?