ROBERT SIEGEL, HOST:
Forty years ago today in Dallas, a white police officer shot a 12-year-old Mexican-American boy. Santos Rodriguez was killed, sparking protests and a riot. Since then, the killing has helped drive the transformation of the local police force.
Lauren Silverman, of member station KERA, has the story.
LAUREN SILVERMAN, BYLINE: Roberto Corona, a community activist, is standing in the middle of a south Dallas cemetery, next to the gravestone of Santos Rodriguez.
ROBERTO CORONA: That incident brought people, communities together. And it's still doing it right now.
SILVERMAN: This morning, dozens gathered here, under a beige tarp, to remember the little boy whose death they say helped change Dallas.
UNIDENTIFIED MAN: We ask you to be with his family, loved ones. Father, those who...
SILVERMAN: On July 24th, 1973, Santos Rodriguez and his 13-year-old brother, David, were pulled from their home, handcuffed and put inside a police car. Officers accused them of robbing $8 from a vending machine. They denied it. Officer Darrell Cain played a game of Russian roulette. The first time he pulled the trigger, nothing happened. The second time, it fired. Twelve-year-old Santos died in that squad car, his blood soaking his brother's feet.
Cain was convicted of murder and sentenced to five years. He served half that.
ALBERT VALTIERRA: This is a very emotional issue. The killing of Santos Rodriguez galvanized our community.
SILVERMAN: Albert Valtierra is president of the Dallas Mexican American Historical League. After decades of segregation and discrimination, he says, in the '70s, the Latino community was finally getting established in Dallas.
VALTIERRA: We were buying houses, we're getting good jobs, but there was still resistance from the powers that be, so we had to go out and claim the power for ourselves.
SILVERMAN: Four days after Santos died, activists came together for a protest march to city hall.
RENE MARTINEZ: It was hotter than today.
SILVERMAN: Triple digits, in fact. Rene Martinez was 25 and helped lead the protest.
MARTINEZ: This was really the first time that Mexican-Americans had organized to have such a protest.
SILVERMAN: Thousands filled the streets on that scorching summer day, chanting in Spanish, justice for the people. The tension came across in coverage at the time.
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UNIDENTIFIED MAN #2: Police motorcycles were set afire and several downtown shop windows were shattered.
SILVERMAN: Five officers were injured, and more than 30 people arrested. Martinez, who is now president of the local League of United Latin American Citizens chapter, says the riot pushed city leaders into action.
MARTINEZ: These were men that said, you know, we've had this tragedy, we're having protests, we've got to change.
SILVERMAN: In the decades that followed the shooting, Mexican-Americans in Dallas grew from a small minority to more than a third of the city's population. They began to win seats on the city council and the school board. The biggest transformation, however, was in the Dallas Police Department.
CYNTHIA VILLAREAL: I'm Cynthia Villarreal.
SILVERMAN: Villareal was the first Latina to put on the Dallas Police uniform in 1975, two years after Santos was killed. Today, she ranks second only to the police chief.
VILLAREAL: It wasn't very diverse. It was white male, basically.
SILVERMAN: Discriminatory policies had shut out people like Villareal. She was eager to join. Her family in south Texas was nervous.
VILLAREAL: When they found out I was applying here at Dallas they said, oh no, they don't like Hispanics there. They just killed a little boy over there. My grandfather thought there were all kinds of problems up here in Dallas.
SILVERMAN: Villareal says it took decades to improve the relationship between Latinos and the police. But today, almost half of the force are minorities. She says the killing of Santos helped drive that change. For NPR News, I'm Lauren Silverman in Dallas.