For more than a week, my phone has been ringing like an ice-cream truck on an August afternoon. This was because an AP reporter recently learned of Department of Justice plans to reopen the 1955 Emmett Till lynching case. Federal officials say the decision was spurred by revelations in my book, The Blood of Emmett Till, published a year and a half ago.

Carolyn Bryant, the white woman whose kinsmen lynched 14-year-old Emmett Till, admitted to me that she had borne false witness at their murder trial in Mississippi. Since lying on the stand in 1955, Carolyn had not uttered a public word until our interview.

Neither her perjury nor the DOJ's reopening of the case seemed like breaking news to me. I had seen her lawyer's notes, penned five days after the murder, which record that Carolyn told him the boy "insulted" her. Nothing more.

Seven witnesses endured the terror when Roy Bryant and J.W. Milam barged into the house with pistols at 2:30 a.m. and ranted about the boy "that done the talking up at Money." No mention of assault.

This evidence is crumbs compared to the 8,000 pages the FBI amassed when they reopened the case from 2004 to 2006. Agents also exhumed the body and unearthed a long-hidden trial transcript but found nothing to sustain a prosecution.

In 2007, a racially mixed Mississippi grand jury sifted through the vast evidence and voted 19-0 not to indict Carolyn. District Attorney Joyce Chiles, a local black woman who shared "their rage," praised the jurors for avoiding conclusions "based solely on emotion."

An FBI agent called two months after my book came out to say that the DOJ planned to reopen the case. I made it clear I supported any possible justice for the Till family and sent the DOJ my research. I also expressed suspicion about the Attorney General's striking conversion to the cause of racial justice.

Jeff Sessions' record on civil rights justifies doubt. As a U.S. attorney, he battled a court order that mandated equal funding for resegregated black schools. As a U.S. senator, Sessions called the Voting Rights Act "a piece of intrusive legislation." When the Supreme Court gutted that landmark achievement of the civil rights movement, he applauded this "good news … for the South."

Among his first acts as attorney general was to reverse the DOJ's stance on voting-rights cases and then back two North Carolina laws — one the U.S. Court of Appeals ruled "target[s] African Americans with almost surgical precision," the other the Supreme Court called a "racial gerrymander."

I sent the DOJ my research over a year ago, but only now, beset by outrage at the detainment of immigrant children without clear plans to reunite them with their parents, did the Trump administration launch this civil-rights charade. Their attack on voting rights persists. What better billboard to shore up the brand than the most notorious racist crime in American history?

Regardless of why Sessions reopens this case — I hope yet unseen evidence justifies it — America must never forget the lynching of Emmett Till.  Three days after the Milam-Bryant clan tortured Emmett to death and rolled him into the Tallahatchie River, his bloated corpse rose to confront our nation's broken moral compass.  His mother, Mamie Till-Mobley, examined his gouged-out eye, clipped ear, shattered skull, and insisted on an open-casket funeral to "let the people see what they did to my boy."

Mrs. Till-Mobley then did something all but unimaginable at the time — she and her allies leveraged the power of black Chicago's community institutions to organize a multicolored coalition that helped win the Civil Rights Act and the Voting Rights Act, create a new black sense of self and set ablaze a compelling vision of democratic possibility. Her boy's name still echoes: "Tamir Rice, Emmett Till / How many black kids will you kill?"

Justice for Emmett Till in the narrow sense seems unlikely. The best way to win justice for him now is to join the struggle that his mother prayed would give this horror meaning.  "Lord, take my soul," she pleaded beside his casket, "show me what you want me to do and make me able to do it."

Timothy Tyson is senior research scholar at the Center for Documentary Studies at Duke University and author of "The Blood of Emmett Till" (2017).