A man suspected of killing six people at a 4 July parade near Chicago planned the attack for weeks, police say.
Law enforcement believe that Robert Crimo III, 21, legally bought the high-powered rifle he used in the attack.
The suspect is believed to have disguised himself in women’s clothing to escape the scene with the fleeing crowd, officials added.
Some 30 people were also injured in the shooting on Monday at Highland Park’s Independence Day parade.
Speaking at a press conference, Lake County Major Crime Task Force spokesman Chris Covelli said multiple firearms belonging to Mr Crimo were recovered – all purchased in the local area.
In addition to the rifle used in the attack, police recovered “another rifle in his vehicle when he was pulled over by police,” Mr Covelli said.
Police say they are still piecing together information about the shooting, during which the suspected gunman is accused of firing more than 70 rounds.
Law enforcement officials said that the victims were targeted at random, and that there was no information to suggest that the attack was motivated by racial or religious hatred.
After blending into the crowd, police say they believe Mr Crimo walked to his mother’s home, from where he later drove off in her vehicle.
Police arrested the suspect while driving the car later on Monday, where he was discovered with a second rifle that was similar to the one used in the attack.
More firearms were also found in Mr Crimo’s home, police said, but did not provide any more details.
Authorities are still considering what criminal charges to bring against Mr Crimo, who they believe acted alone.
This breaking news story is being updated and more details will be published shortly. Please refresh the page for the fullest version.
