Aurora Police Chief Kristen Ziman said the shooter, identified as 45-year-old Gary Martin, worked at the sprawling industrial complex in Aurora, 40 miles (65 km) west of Chicago, but did not say what may have motivated the attack.
Van Dyke could have received up to 20 years in prison for second-degree murder and up to 30 years for each of 16 counts of aggravated battery - one count for each shot he fired at 17-year-old McDonald, who was carrying a knife.
The men are accused of killing Trenton James Cornell-Duranleau, a Michigan native who had been living in Chicago, last month. Chicago police said Duranleau suffered more than 40 stab wounds, including "mutilations,'' to his upper body.
Paris Poe goes before a Chicago federal judge Friday a day after Hobos leader Gregory "Bowlegs'' Chester was sentenced to a 40-year prison term. Jurors found Poe carried out the most chilling of multiple Hobos murders. He fatally shot government witness Keith Daniels in 2013.
A Northwestern University professor and a University of Oxford employee wanted in the brutal stabbing death of a Chicago man were arrested in California on Friday and will be returned to Chicago for interrogation, federal and local authorities said Friday.