Washington: US Attorney General Eric Holder on Monday lamented the "tragic, unnecessary" shooting death of black teenager Trayvon Martin and called for a dialogue on issues raised by the killing.
But Holder, speaking to an African American sorority, was silent on whether the Justice Department would pursue civil rights charges against George Zimmerman, the neighbourhood watch volunteer acquitted late Saturday of Martin`s killing.
"The Justice Department shares your concern -- I share your concern -- and, as we first acknowledged last spring, we have opened an investigation into the matter," Holder said.
"Independent of the legal determination that will be made, I believe that this tragedy provides yet another opportunity for our nation to speak honestly about the complicated and emotionally-charged issues that this case has raised," he said.
White House spokesman Jay Carney, meanwhile, said President Barack Obama would not involve himself in the decision about whether to press federal charges.
"He has no opinion to express about the disposition of how the Justice Department would look at this," said Carney.
Obama appealed for calm yesterday after the verdict was handed down in Florida, setting off a wave of angry protests in US cities.
"We should ask ourselves, as individuals and as a society, how we can prevent future tragedies like this," Obama said.
"As citizens, that`s a job for all of us. That`s the way to honour Trayvon Martin."
Zimmerman was accused of pursuing Martin through a gated community in the town of Sanford and shooting him during an altercation on the rainy night of February 26, 2012.
The defence successfully argued that Zimmerman -- who is half white and half Latino -- fired his handgun in self-defence after the teen wrestled him to the ground and started slamming his head against the pavement.
Critics of the verdict argue that Zimmerman racially profiled the unarmed black teen -- who had no criminal record -- and was able to kill him with impunity because of a biased criminal justice system.
Zimmerman is the only living witness to how the fight began.