The man in custody after the death of six people at a Fourth of July parade in suburban Chicago appeared to have spent weeks planning the attack, and wore women’s clothing during his escape, officials said on Tuesday.

Deputy chief Christopher Covelli of the Lake County Sheriff’s office said the man, who had not been charged as of Tuesday morning, had purchased his rifle legally in the Chicago area. He had another rifle in his car when he was taken into custody on Monday evening, about eight hours after the attack, the chief said.

More than 30 people were wounded in the shooting, which took place on Monday morning in Highland Park, Illinois, a lakefront suburb north of Chicago, officials said. Chief Covelli said the shooting appeared to have been random, with no indication that the victims had been targeted because of race or religion.

The shooting came a week and a half after President Biden signed the most significant gun measure to clear Congress in nearly three decades, but it was unclear whether any of the new regulations would have stopped the gunman. The mayor of Highland Park said the suspect obtained his weapon legally; he carried out his attack in a state that already has some of the nation’s toughest gun laws, but is bordered by states where firearms are much easier to come by.

The attack came minutes into the start of a charming Fourth of July parade, with band members and politicians strutting down the street, as horrified spectators realised the noise from a nearby rooftop wasn’t fireworks but a high-powered rifle spraying bullets into the crowd.

The attack sent the police on a sprawling manhunt that forced residents to shelter in place for much of the day and prompted neighbouring cities to cancel their holiday events. About eight hours later, the police said they had taken into custody Robert E. Crimo III, 21, described as a person of interest, after a brief chase. (The police had originally said Crimo was 22 but corrected that on Tuesday.)

Even in a country battered from the constancy of mass violence — at grocery stores and elementary schools and on urban street corners — the carnage in Illinois proved shocking. According to the Gun Violence Archive, a non-profit research group, the shooting on Monday was the 15th this year in which at least four people were fatally shot in the US. For reasons that remained unclear to the police on Monday evening, officials said Crimo had climbed onto a rooftop with a rifle and begun firing into a sea of families in lawn chairs who were celebrating Independence Day.

“My wife looks up and screams, ‘Get up, run. Get up, run,’” said Shawn Cotreau, 47, a Massachusetts resident who was visiting family in Illinois, and who said he initially thought there were firecrackers nearby. Police officers, who were already assigned to the parade route, arrived and rushed to help the wounded, the authorities said. Victims ranged in age from 8 to 85, doctors said.

New York Times News Service