As he prepares to leave office in the next week or two, Atty. Gen. Eric H. Holder Jr. called for new civil rights legislation, warned of the mounting threat of terrorism and described his worst day in office in a round of farewell media interviews Friday.
Noting that the Justice Department said this week it would not prosecute George Zimmerman for shooting Trayvon Martin, an unarmed black youth in Sanford, Fla., Holder said the law needed to be changed to make such prosecutions easier.
Before he steps down, Holder is expected to announce that the Justice Department will not seek to prosecute Darren Wilson, the police officer in Ferguson, Mo., who shot and killed Michael Brown last year in a confrontation over a jaywalking offense. The case sparked widespread public protests and clashes with police.
"I'm going to say that I think we do need to change the law, that the standard [of proof] is too high," he told NBC News. "We need to allow the federal government to be a better backstop in examining these cases."
Holder said U.S. authorities have hundreds of people under surveillance as the risk of terrorism has increased from the Islamic State and other groups, but said federal agencies have improved their capacity to deal with the danger of domestic extremism.
James Comey, the FBI director, said in a speech earlier this week that the bureau has investigations open in all 50 states of people in varying stages of radicalization.
On Wednesday, the FBI arrested three men living in Brooklyn, N.Y., on charges of aiding Islamic State after one of them used an Uzbek-language website to try to join the group. The case highlighted both the terrorist group's ability to recruit online, as well as government efforts to mine websites for signs of radicalization.
Holder refused to confirm widespread media reports that identified the Islamic State executioner in Syria known as "Jihadi John" as Mohammed Emwazi, a 26-year-old Kuwait-born man who was raised in London.
But Holder vowed on ABC News to "hold accountable ... the people who are responsible for these barbaric acts. "
Holder said his worst day on the job was Dec. 14, 2012, when a gunman killed 20 children and six adults in Sandy Hook Elementary School in Newtown, Conn., one of the deadliest mass shootings in U.S. history.
When he visited the school, Holder said, "I cried. The men and women who were up there that day cried. We hugged each other. That was, without question, the worst day."
Holder has spent six years as the nation's top law enforcement official. The full Senate is expected to vote early next month to confirm his successor, Loretta Lynch, now U.S. attorney for the Eastern District of New York.