UPDATED at 7:55 p.m. ET:
Police have arrested 21-year-old Robert "Bobby" E. Crimo III as a "person of interest" in a mass shooting at a Fourth of July parade in Highland Park, Illinois. Crimo was apprehended in Lake Forest after an attempted traffic stop led to a brief chase. He was taken into custody and transported to the Highland Park Police Department.
Authorities are continuing their investigation and said Crimo is considered a "person of interest" and won't be named as a suspect until they can positively connect him to the scene.
At a press briefing just after 5:30 p.m. Eastern time, officials identified Crimo, who's from the Chicago area, as the suspected shooter and said he was driving a 2010 silver Honda Fit with the Illinois license plate DM-80653.
City officials also spoke at a press briefing at 3:30 p.m. local time, where Jennifer Banek provided an update on the coroner's investigation and confirmed that five of the shooting victims who died at the scene were adults. The age of the spectator who was pronounced dead at an area hospital was not released.
Fire Chief Joe Schrage said the fire department transported 23 victims to area hospitals. One of the victims transported by the fire department was a "critically injured" child.
Injuries "were gunshot wounds, and that varied from [the] abdomen to limbs," Schrage said. "The crews were on scene very quickly. There were bystanders as well who rendered aid ... they were quick to tie tourniquets and do bleeding control which definitely assisted the fire department on scene."
Other injured spectators drove themselves to area hospitals for treatment or were transported by other parade attendees.
Highland Park Police Commander Chris O’Neill asked residents with any information about the suspect or photos and video footage from the scene to call investigators at 1-800-CALL-FBI.
At least six people were killed in a mass shooting at a Fourth of July parade in Highland Park, Illinois, and as many as 24 other spectators who sustained serious and critical injuries are being treated at area hospitals.
The city of Highland Park is now on lockdown after law enforcement agencies ordered residents and workers at nearby businesses to shelter in place as swat teams go door-to-door to search for the suspect who might be armed.
At a press conference, Highland Park Police Commander Chris O’Neill, the incident commander on scene, said the suspect is believed to be a white man, who is approximately 18- to 20-years-old, with long black hair, a small build and wearing a white or blue T-shirt.
Police believe the suspect carried out the mass shooting from a rooftop where they recovered a high-powered rifle.
At a subsequent press conference at 2 p.m. local time, Chris Covelli with the Lake County Sheriff's Office confirmed that "firearm evidence was located on a rooftop of a nearby business that was secured."
Covelli said more than 100 law enforcement officers were called to the parade scene or dispatched to find the suspected shooter. Investigators are also scouring social media to find clues as to why the suspect committed the mass shooting. He said it appears that the shooter targeted spectators at random.
He added that the information is preliminary, but it's believed five people died at the scene and one victim was pronounced dead at an area hospital. The wounded were transported to various hospitals in Lake and Cook Counties where their injuries are being treated.
Covelli added that the parade was "three-quarters of the way through" when the suspect began shooting. "Very random, very intentional, and a very sad day."
Multiple agencies are working with local authorities and state police on the investigation. Highland Park police are leading the initial investigation and the Lake County Major Crime Task Force is working in conjunction with the FBI to process the scene.
State police have asked anyone with photos or video footage from the parade to share it with the Highland Park Police Department, particularly footage near 2nd Street and Central Avenue. Police are also asking local businesses in the area to share their security footage.
"As far as the investigative aspect goes, and this is two-pronged at this time, number one, we are aggressively looking for the individual who is responsible for this shooting," Covelli said. "Number two, we have a criminal investigation that is occurring simultaneously. We are asking anybody with any video surveillance that they may have, please review your cell phones if you were snapping pictures ... that could help investigators."
Mayor Nancy Rotering spoke at the first news conference Monday afternoon, expressing her grief that around 10:14 a.m. local time, "our community was terrorized by an act of violence that has shaken us to our core."
"Our hearts go out to the families of the victims at this devastating time. On a day that we came together to celebrate community and freedom, we are instead mourning the tragic loss of life and struggling with the terror that was brought upon us," she added.
This is a developing story and will be updated.
Correction: An earlier version of this article misidentified Robert E. Crimo III's age as 22 based on initial reports. He is 21.