Eric Holder, the US attorney general, repeated Tuesday his promise that 17 year old Trayvon Martin's  "tragic and unnecessary" killing by George Zimmerman, who was not found guilty of the murder by a Florida court, would be fully investigated by the Department of Justice. Speaking at the annual convention of the National Association for the Advancement of Colored People (NAACP), Holder said The Department of Justice would consider all available information before determining what action to take. "But independent of the legal determination, I believe this tragedy provides yet another opportunity for our nation to speak honestly and openly about the complicated and emotionally-charged issues that this case has raised," he said. He said  the protests after Zimmerman's acquittal, were 'largely' peaceful apart from a small number of arrests in California.

"In the days leading up to the weekend's verdict, some predicted and prepared for riots and waves of civil unrest across the country. Some feared that the anger of those who disagreed with the jury might overshadow and obscure the issues," he said. "Those who act in a contrary manner do not honor the memory of Trayvon Martin."

Referring to his childhood, as the country's first African-American attorney general, Holder told of the progress that still needed to be made in race relations in the US.

"Years ago, some of these same issues drove my father to sit down with me, to have a conversation about how, as a young black man, I should interact with the police, what to say and how to conduct myself, if I was ever stopped or confronted in a way I thought was unwarranted," he said adding he had to have a similar conversation with his own 15-year-old son, "not to burden him with the baggage of eras long gone, but to make him aware of the world he must still confront."

Holder also criticized the US's 'stand-your-ground law' that eliminated "the commonsense and age-old requirement" that people who felt threatened had a duty to retreat.

"These laws try to fix something that was never broken," he said. "We must stand our ground to ensure that our laws reduce violence and take a hard look at laws that contribute to more violence than they prevent. By allowing and perhaps encouraging violent situations to escalate in public, such laws undermine public safety. The list of resulting tragedies is long and unfortunately has victimized too many who are innocent."