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 The white police officer who killed Michael Brown has resigned from the Ferguson Police Department, his attorney said Saturday, nearly four months after the fatal confrontation with the black 18-year-old that fueled protests in the St. Louis suburb and across the nation.

Darren Wilson, 28, has been on administrative leave since the shooting on Aug. 9. His resignation was announced Saturday by one of his attorneys, Neil Bruntrager. The resignation is effective immediately, Bruntrager said. He declined further immediate comment but said he would release more details Saturday night.

The attorney for the Brown family, Benjamin Crump, did not immediately return phone and email messages from The Associated Press seeking comment.

A grand jury spent more than three months reviewing evidence in the case before declining in November to issue any charges against Wilson. He told jurors that he feared for his life when Brown hit him and reached for his gun.

The U.S. Justice Department is still conducting a civil rights investigation into the shooting and a separate probe of police department practices.

The news of Wilson’s resignation didn’t seem to appease a small group of protesters who stood outside of the Ferguson police department on Saturday night.

‘‘I've been protesting out here since August,’’ said Rick Campbell, who added that he didn’t care that Wilson had resigned.

Several other protesters who were asked to comment shrugged their shoulders or expressed disinterest.

‘‘We were not after Wilson’s job,’’ civil rights activist the Rev. Al Sharpton said in a statement to AP. ‘‘We were after Michael Brown’s justice.’’