President Donald Trump has repeatedly floated sending National Guard troops to Chicago to aid in deportation efforts and to crack down on crime in a similar manner to Washington, D.C.
"It is unacceptable for military personnel and Department of War civilians to celebrate or mock the assassination of a fellow American," Pentagon spokesperson Sean Parnell wrote on X. "The Department of War has zero tolerance for it."
The inscriptions on the ammunition suggest the suspect was steeped in antifascist politics and online meme culture, although more remains to be known about his motivations.