The first-ever U.S. Justice Department review of the 1921 Tulsa Race Massacre concluded Friday that while federal prosecution may have been possible a century ago there is no longer an avenue to bring a criminal case more than 100 years after one of the worst racial attacks in U.

The Justice Department’s conclusion follows an investigation of the 1921 atrocity in Oklahoma in which up to 300 Black residents were killed.

The Department of Justice found in a newly released report that though the Tulsa Race Massacre was a “systematic” and “coordinated” attack that transcended mere mob violence, any legal