Attorney General Eric Holder Jr. is in the middle of a political and legal balancing act following the acquittal of George Zimmerman in a racially-charged murder case, with civil rights leaders calling on U.S. Department of Justice to take legal action and federal laws that might not make that possible.

In his first comments since Saturday’s not-guilty verdict and subsequent protests around the country, Holder told the Delta Sigma Theta sorority in Washington on Monday that civil rights leaders are right to be concerned about the “unnecessary” shooting death of Trayvon Martin in Sanford, Fla., last year.