Dispatcher: Are you following him?

Zimmerman: Yeah.

Dispatcher: OK, we don’t need you to do that.

The first tragedy of the Trayvon Martin case is that it didn’t have to happen. George Zimmerman didn’t have to trail the teenager through the darkened streets of the gated Florida community, didn’t have to get out of his truck. He was told not to. But he did.

In the struggle that followed, the unarmed boy was shot and killed — an unarmed African-American teen, shot and killed by a Neighborhood Watch volunteer who found his presence “suspicious.”

It’s those details that caused a public outcry when police and prosecutors initially declined to charge Zimmerman with a crime.

Those same details hang over Saturday’s verdict.

The nation should respect the jury that found Zimmerman not guilty of second-degree murder. Defense attorneys argued that he fired in self-defense, and prosecutors couldn’t prove otherwise. Without enough evidence to challenge Zimmerman’s version of events, jurors had no choice but to acquit. We saw a criminal justice system that is designed to protect the rights of the accused, that rightly sets a high bar for a criminal conviction.

The jurors reached a unanimous verdict. The jurors did their job.

The same can’t be said of police and prosecutors in the aftermath of the shooting. It is their cavalier response — not the verdict — that compounds this tragedy.

Sanford, Fla., police quickly accepted Zimmerman’s explanation that he pulled his gun because he felt his life was in danger. They weren’t duly troubled by his remarks that Martin was a “punk” who “looks like he’s up to no good.” They didn’t sufficiently question his account or his motives. They shrugged it off.

An angry public demanded to know whether police and prosecutors would have scrutinized the evidence more closely if Martin were white. It was, and is, a fair question.

More than a million people signed an online petition demanding Zimmerman’s arrest. The U.S. Justice Department launched an investigation into Martin’s death. The Sanford police chief stepped down, and a special prosecutor was named to handle the case. Six weeks after the shooting, Zimmerman was charged with second-degree murder.

The fact that Zimmerman was eventually acquitted of the charge — and the lesser charge of manslaughter, which the jury also rejected — doesn’t validate the cursory dismissal by law enforcement back in February 2012. This case deserved to be examined thoroughly and adjudicated.

As the case moved to trial, many of those who led the campaign stressed that what they demanded was not an outcome, but a trial. But many now are bitterly disappointed at the result.

The trial was fair. The evidence came up short. The outrage was that there almost wasn’t a trial at all.