The 21-year-old man accused of opening fire at a suburban Chicago Fourth of July parade, killing seven people and injuring dozens of others, plotted another attack in Madison, Wisconsin, authorities said Wednesday.
After fleeing the scene of the parade, Robert "Bobby" Crimo III "was driving around, saw a celebration in Madison," and "contemplated another attack," with "60 rounds on his body at that point," authorities said at a news conference Wednesday.
But he "had not done enough planning" and decided not to do it, authorities said.
After returning from Wisconsin, Crimo was apprehended at at traffic stop in Lake Forrest, Illinois, Monday evening.
Crimo is charged with seven counts of first-degree murder in the wake of Monday morning's mass shooting in Highland Park, Illinois. More charges are expected, Lake County State’s Attorney Eric Rinehart said.
Crimo, who appeared in court via Zoom for his first appearance Wednesday, showed no emotion as a prosecutor outlined the attack and read the victims' names.
Prosecutors said that Crimo confessed to Monday morning's parade massacre.
Crimo is accused of taking his legally purchased high-powered rifle and opening fire on paradegoers from a roof of a business.
A witness reported seeing an individual with a gun on a building rooftop "scanning the ground with a gun," Assistant State’s Attorney Ben Dillon said.
On the rooftop, police discovered three empty 30-round magazines and 83 spent shell casings, prosecutors said.
Crimo told police he wore women's clothing during the shooting and used makeup to hide his facial tattoos and blend in with the crowd, prosecutors said.
Dillon said Crimo was spotted running from the scene with a black bag over his shoulder, and an object wrapped in cloth fell out of the bag and onto the pavement. The object was a Smith and Wesson M&P 15 semi-automatic rifle, Dillon said.
A second weapon, also purchased legally by Crimo, was found in the car when he was apprehended, police said.
Crimo did not enter a plea during Wednesday's appearance and was appointed a public defender.
Crimo was ordered held without bond. He is set to return to court for a preliminary hearing on July 28.
When the gunfire began at Monday's parade, revelers fled in panic, leaving behind empty strollers, overturned chairs and half-eaten sandwiches.
"Bodies were horribly, horribly, horribly injured from, you know, guns and bullets that were made for war -- not for parades," witness Dr. David Baum said of some of the victims.
"The paramedics went quickly and assessed the damages -- saw bodies that were blown apart and put a blanket over them quickly. And then went on to try and help other people," Baum told ABC News. "These are injuries that nobody should have to see."
Authorities believe the massacre had been planned for weeks.
No motive is known, police said. When asked by reporters if the gunman targeted anyone specifically, police said the "shooting appears to be completely random."
ABC News' Aaron Katersky and Jeff Cook contributed to this report.