BIRMINGHAM, Ala. (AP) — The Justice Department’s decision to close its investigation of Emmett Till’s slaying all but ended the possibility of new charges in the teen’s death 66 years ago, yet agents are still probing as many as 20 other civil rights “cold cases,” including the police killings of 13 Black men in three Southern states decades ago.

The department is reviewing the killings of six men shot by police during a racial rebellion in Augusta, Georgia, in 1970, according to the agency’s latest report to Congress. The city best known for hosting golf’s Masters Tournament had been engulfed by riots after a Black teenager was beaten to death in the county jail.

The agency also is investigating the killings of seven other Black men involved in student protests in South Carolina, Mississippi and Louisiana during the societal upheaval of the late 1960s and early ‘70s. And investigators are looking at cases in which seven more individuals were killed, including a girl in Pennsylvania, the report showed.

Suspects were already tried and acquitted in some of these killings, making prosecution on the same charges all but impossible. Fading memories, lost evidence and the death of potential witnesses almost always pose problems in the quest for justice in decades-old cases.

Still, in Georgia, a leader of a group formed to tell the story of the “Augusta Six” — John Bennett, Sammie L. McCullough, Charlie Mack Murphy, James Stokes, Mack Wilson and William Wright Jr. — hopes some type of justice will prevail for the victims’ families, even if it’s not a criminal conviction.

“With the Justice Department’s stamp on it, even a statement that the killings were wrongful would help even if there’s no prosecutions. I think that would be very helpful for the community,” said John Hayes of the 1970 Augusta Riot Observance Committee.

The Justice Department said Monday it had ended its investigation into the 1955 lynching of Till, the Black teenager from Chicago who was tortured, killed and thrown in a river in Mississippi after witnesses said he whistled at a white woman at a rural store. Two white men who were acquitted by all-white juries later confessed to the killing in a paid magazine interview, but both are dead and officials said no new charges were possible.

The Justice Department Cold Case Initiative began in 2006 and was formalized the following year under a law named for Till, whose slaying came to illustrate the depth and brutality of racial hatred in the Jim Crow South. Initially created to investigate other unresolved cases of the civil rights era, it was later expanded to include more recent cases, including killings that occurred in cities and on college campuses during demonstrations against the Vietnam War and racism.

In Augusta, as many as 3,000 people were estimated to have participated in protests and rioting that followed the death of 16-year-old Charles Oatman, who was beaten to death while being held in the jail. Frustration over his death and years of complaints over racial inequity erupted in unrest that left an estimated $1 million in damage across a wide area.

Once the gunfire ended early on May 12, 1970, six Black men were dead from shots fired by police, authorities said. Two white officers were charged, one with killing John Stokes and the other with wounding another person, but both were acquitted by all- or mostly white juries.

Families are still grieving, Hayes said, but the killings generally aren't discussed much in Augusta.

“There’s a lot of trauma there and things people don’t want to bring up,” said Hayes, whose group is in contact with relatives of half the victims.

The other police shootings under review were sparked by campus demonstrations amid simmering resentment over mistreatment of Black people.

Three men were killed on Feb. 8, 1968, during protests to desegregate a bowling alley near South Carolina State College in Orangeburg, South Carolina. Nine state police officers were acquitted in what came to be known as the “Orangeburg Massacre,” and a campus sports arena now honors the three victims, Samuel Hammond, Delano Middleton and Henry Smith.

Phillip Gibbs and James Earl Green were killed by police during a student demonstration at Jackson State University in Jackson, Mississippi, on May 15, 1970, and Leonard Brown and Denver Smith were gunned down during a protest at Southern University in Baton Rouge, Louisiana, on Nov. 16, 1972. No one was ever prosecuted for the killings in Jackson or Baton Rouge.

The seven other cases still under review by the Justice Department span the years 1959 through 1970 and involve individuals. The victims include 9-year-old Donna Reason, killed on May 18, 1970, when someone threw a Molotov cocktail into the home of her mixed-race family in Chester, Pennsylvania. No one was ever arrested.