Again, a black teen is shot, but cases are not the same

• Both defendants claimed self-defense
• No one saw the George Zimmerman-Trayvon Martin confrontation from start to finish
• When Michael Dunn shot Jordan Davis%2C there were several witnesses

Once again, the nation watches as the man accused of fatally shooting a black teen is tried in Florida.

Michael Dunn, 47, shot Jordan Davis, 17, on Nov. 23, 2012. Within days, the public began comparing him to George Zimmerman, then 28, who killed Trayvon Martin, also 17, on Feb 26, 2012.

The same Florida prosecutors say both men murdered unarmed boys. Dunn and Zimmerman are adamant that, in fear for their lives, they acted in self-defense.

Dunn testified Tuesday that after firing several shots at Davis, he drove away because he thought no one had been hurt.

Closing arguments could come Wednesday.

Both cases have sparked outrage from people who say the killings show the deadly effects of racial profiling.

"From a social and a family perspective, there are a lot of similarities," says Keisha Bentley-Edwards, a professor at the University of Texas at Austin who studies race, adolescence and academic and social development. "You have unarmed black teens who were acting normally and treated in a very egregious fashion. You have someone without any official authority imposing a sense of authority and enforcing it with lethal means."

Dunn, a software engineer, is on trial now on charges of first-degree murder, three counts of attempted murder and shooting or throwing a deadly missile. He fired 10 bullets into a Dodge Durango with four teens inside during an argument over loud music in a Jacksonville parking lot, police say. Dunn testified that he thought he saw a gun and that Davis got out of the car and threatened him.

Zimmerman, a neighborhood watch volunteer, was acquitted of second-degree murder last year after shooting Martin in a gated Sanford, Fla., community. Zimmerman said he killed Martin after the teen attacked him.

Bentley-Edwards says both cases cause black parents to consider how to protect their children from racial stereotypes that she believes motivated both Zimmerman and Dunn. She is not alone.

Protests and Internet campaigns have linked the deaths of Martin and Davis for more than a year.

However, Randy Reep, a criminal defense attorney in Jacksonville, says that after race and self-defense claims, the similarities end. A chief problem for Dunn, Reep says, is that he left the scene and didn't talk to police until authorities came to him the day after the shooting. Zimmerman stayed.

"Zimmerman said, 'Everybody listen to me, this is what I did,' " says Reep, a former prosecutor. "That posits someone who doesn't think what they did was wrong. Dunn basically ignored it for almost a day — at least in the eyes of the jury."

Reep is convinced Dunn's actions after the shooting will lead to his conviction. He adds that prosecutors have a stronger case than they did with Zimmerman because several people, including Davis' three surviving friends, witnessed the shooting.

With Zimmerman, no one else saw the confrontation from start to finish. Because he didn't testify, Zimmerman told the jury his side of the story and avoided cross-examination. Even more, Zimmerman had injuries that showed evidence of a fight. Dunn had none.

"There is no question about the sequence of events,"Jason Johnson, a political science professor at Hiram College in Hiram, Ohio, says of the Dunn shooting. "In the Zimmerman trial, what it really boiled down to was who started the fight, and that was not something anyone actually knew."

Prosecutors seem to have learned from the Zimmerman trial and have prepared their witnesses better, says Areva Martin, a Los Angeles-based attorney.

She pointed to the much-discussed hostility between witness Rachel Jeantel, Martin's friend who was on the phone with him when the incident began, and defense attorney Don West. This time around, Davis' friends, who watched the teen die, remained calm during questioning.

"The devastation to these young boys is just unthinkable, but yet they were composed and gave such fluid and consistent testimony," Martin says.

Despite the long list of legal differences, speechwriter Therman Evans says both cases make him think of the dangers his black 6-year-old son might have to face one day. Still, he isn't following Dunn's trial as closely as he did Zimmerman's.

"At some point, you get a little tired and a little disgusted," says Evans, 41, of Upper Marlboro, Md. "You sort of retreat within yourself and say, 'What can we do about it?' Another black boy is lost over what? Loud music."

Contributing: Rick Neale, Florida Today