A police officer reacts as he walks in downtown Highland Park, Ill., a suburb of Chicago, Monday, as law enforcement continues a search for the suspected gunman who killed at least six

This undated handout photo provided by the City of Highland Park Police Department shows Robert (Bobby) E. Crimo III

Law enforcement works the scene after a mass shooting at a Fourth of July parade on July 4, in Highland Park, Illinois

A Lake County police officer walks down Central Ave in Highland Park on Monday

The scene following a shooting in Highland Park on July 4

Nicolas Toledo, one of the victims in the shooting at the 4th of July parade shooting in Highland Park, Ill., a suburb of Chicago, is pictured in an undated family photo

Police investigate outside the home of the mother of the man detained in the mass shooting at a Fourth of July parade on July 4, 2022 in Highland Park, Ill