The alleged gunman was identified as Anthony N. Ferrill, 51, who had worked as an electrician for more than 20 years, according to a law enforcement source who spoke to the Milwaukee Journal Sentinel and online employment records.
This one was not the usual. His age. His race. He used two handguns.
From the second link
A co-worker who asked not to be identified for fear of being disciplined said that Ferrill believed he was being discriminated against because he was African-American and that he frequently argued with at least one of the victims, a fellow electrician.
The co-worker said Ferrill often watched movies on his phone during the day, which the other electrician took issue with, and that the two accused each other of going into each others’ offices and stealing tools or tampering with computer equipment.