DeWayne Craddock, a city engineer who went on a shooting rampage in 2019, had been “fixated for years” on criticism at work, the F.B.I. said.
The police chief described a “chaotic” night involving what appeared to be three instances of gunfire.
In the last five years, there have been at least 29 shootings with four or more fatalities, according to a database compiled by the Violence Project.
With many districts across the country opting for online learning, a range of technical issues marred the first day of classes.