The 1973 death of Santos Rodriguez was almost unspeakably barbaric. The 12-year-old and his brother David were picked up from their grandparents' house in what was then Little Mexico (now Uptown) in the early hours of July 24 and taken to a Fina station on Cedar Springs Road, where someone had just stolen a few bucks from a soda machine. Officer Darrell Cain and his partner knew the boys' history of shoplifting and burglary and figured they might be involved. A trip would be just the thing to jog their memories.

David Rodriguez, now 53, recounted Cain's interrogation techniques in a recent interview with The Dallas Morning News.

They were trying to force us to say that we burglarized a Coke machine out of $8. We had nothing to do with that that night. He was mostly questioning my brother. When he wasn't getting the answers he wanted, that is when he pulled out his gun. He opened the cylinder with me right next to him. I couldn't really tell if he was emptying it or filling it. He put the gun up to his [Santos'] head. He said, "Now you are going to tell him the truth."

The first time he pulled the trigger of the .357-magnum revolver, there was the click of an empty chamber. The next shot entered his head just below his left ear, killing the boy. Cain said the shooting was an accident. Later that year, he was convicted of murder and sentenced to a whopping five years in prison.

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For the record, the Rodriguez brothers were telling the truth. The fingerprints lifted from the soda machine belonged to someone else. But even had they matched, petty theft is a poor excuse for a back-seat execution, accidental or otherwise, and the black and Hispanic communities saw it as a symptom of a justice system loaded against them.

The most immediate reaction was outrage. Rene Martinez, now president of the District 3 chapter of the League of United Latin American Citizens, was a 25-year-old activist at the time living three blocks from the Fina station. His mom and Santos Rodriguez's mom were friends. He helped organize a community meeting at Pike's Park.

"It was very tense," he says. "There was a lot of anger. A lot of anger at the police department, [a lot of people] wanting to have answers."

It was at the meeting that organizers began planning a weekend march on City Hall. Five thousand people, mostly Hispanic but with some whites and blacks, showed up and made their way from Kennedy Memorial to 1500 Marilla St.

That part of the demonstration was peaceful. But then a second group of marchers showed up, maybe 1,000 strong. They were younger, angrier and drunker than the first, and the protest unraveled into a riot, complete with widespread looting and vandalism. Martinez was standing 50 feet away when one of them unscrewed the gas cap on a police motorcycle and tossed in a match. The burned-out chassis was plastered on the front page of The Dallas Morning News the next morning. But the image that has stuck with Martinez is that of a little Mexican-American woman, maybe 80 years old, walking up to a squad car which rioters had just crushed and angrily wailing on it with a rolled-up newspaper.

Martinez credits then-police-Chief Frank Dyson with showing restraint. He also credits the chief with being open-minded to the reforms being demanded by the community. There were changes to recruitment and officer training. He spurred the creation of an internal affairs department. He invited Martinez and a half dozen others to give race relations training to all patrol units.

It was around this time that The Dallas Morning News proclaimed in an unironic headline that "New Brown Leaders Emerge." Martinez was one. Others who were active in the organizing the community response to the Rodriguez murder and who are still around are then-City Councilman Pedro Aguirre; Richard Medrano, then a leader of the Dallas Brown Berets; and Florentino Ramirez, a lawyer and member of the City Plan Commission.

But to say that Rodriguez's death was a watershed moment in the political identity of the Hispanic community in Dallas is an oversimplification. Young leaders had already been cutting their teeth on school desegregation, which was just beginning in earnest in Dallas in the early 1970s, and in the fight for single-member council districts.

"I like to say that Dallas has missed the '60s," Martinez says. "It didn't go through the civil rights period" that other Southern cities did. "The '70s is really when Dallas began to face civil rights. Arrests, shootings, segregation, apportionment -- all those things."

Community activists and SMU's Embrey Human Rights program are organizing a handful of events to mark the 40th anniversary of Rodriguez's murder. On Wednesday, the anniversary itself, there will be a 10 a.m. memorial at Oakland Cemetery and a 6 p.m. panel discussion at the Latino Cultural Center. At 6:30 p.m. on Saturday, there will be a memorial at Pike Park on Harry Hines Boulevard. You can find more details here.

So, Rodriguez's memory lives on. It's a bit less visceral for the emerging generation of Dallas' Hispanic leaders, but Martinez sees the same spirit motivating the young people who helped organize the school walkout and Mega March in 2006 as the one that spurred him and his fellow leaders four decades ago.