https://www.gannett-cdn.com/presto/2019/05/04/PCIN/b54ff0ff-2b5f-48f2-996e-ea7a2dc56333-cindc5bk-5iaowd8nslsjsnaxovn_original.jpg cincinnati.com today in history, may 4: ohio national guard killed 4 students at kent 2019-05-04 Today History, May Ohio National Guard killed 4 students at Kent State. ..…