Several years ago, the FBI began reopening cold cases from that era — 112 at last count — raising hopes among some for justice. In all but about 20, though, the families of the long dead have received letters, often hand-delivered by F.B.I. agents, that say their cases have been closed, there is nothing more to be done — and please accept our condolences.

https://www.nytimes.com/2013/03/17/us/souths-cold-cases-reopened-but-still-unresolved.html