COLUMBIA, S.C.  — The man accused of slaying nine black church members in Charleston will be indicted on a federal hate crime charge on Wednesday, according to an official close to the case.

The official, speaking on condition of anonymity because the indictment hadn’t been publicly announced yet, told The Associated Press that a grand jury would indict 21-year-old Dylann Roof. The move has been expected since Roof’s arrest after the June 17 shootings at Emanuel African Methodist Episcopal Church in downtown Charleston.

Federal officials have previously said that the shootings generally meet the legal requirements for a hate crime and that federal charges were likely. Roof, who is white, appeared in photos waving Confederate flags, and survivors told police that he hurled racial insults during the attack.

Roof already faces state charges including nine counts of murder. State prosecutors have not said whether they’ll seek the death penalty. Hate crime cases are often challenging for the government because it must prove that a defendant was primarily motivated by a victim’s race or religion as opposed to other factors frequently invoked by defense attorneys, such as drug addiction or mental illness.