Hours after gunfire interrupted the Highland Park, Illinois, July Fourth parade, killing seven people and wounding dozens more, police apprehended the man they believe was responsible.

Robert "Bobby" E. Crimo III, 21, faces seven charges of first-degree murder in connection with the shooting, which authorities said he allegedly carried out by climbing onto the rooftop of a nearby business and opening fire minutes after the parade started, sending paradegoers and participants running for safety.

Investigators believe the suspect planned "this attack for several weeks," Chris Covelli, spokesperson for the Lake County Major Crimes Task Force, said at one of several news conferences Tuesday. The suspect dressed in women's clothing to help conceal his identity, Covelli said, blended in with the crowds as they fled the area, and went to his mother's house.

Law enforcement have yet to establish a motive, but Covelli said there has been no information to suggest the attack was "racially motivated, motivated by religion or any other protected status." There is no indication anyone else was involved, Covelli said.

The suspect was taken into custody soon after police publicly identified him Monday as a "person of interest," whom the FBI said was "being sought for his alleged involvement in the shooting of multiple individuals" at Highland Park's Independence Day parade.

The suspect took his mother's vehicle, and a member of the community saw him, Covelli said. That individual called 911, and then North Chicago police conducted a traffic stop and took him into custody.

He is due in court Wednesday, and Eric Rinehart, state's attorney for Lake County, said he will ask a judge to keep Crimo held without bail. Rinehart said "dozens of more charges" will be added later. Attorney Thomas Durkin is representing Crimo, he confirmed to CNN.

Attorney Steve Greenberg said Tuesday he is representing Crimo's parents and released a statement attributed to them.

"We are all mothers and fathers, sisters and brothers, and this is a terrible tragedy for many families, the victims, the paradegoers, the community, and our own," the statement says. "Our hearts, thoughts, and prayers go out to everybody."

Here's what we know about the suspect:

In September 2019, Highland Park Police went to Crimo's home after a family member reported that he had said he was going to kill everyone, according to Covelli.

"The threat was directed at family inside of the home," he said.

Police confiscated a collection of bladed items -- 16 knives, a dagger and a sword -- but made no arrests because there were no signed complaints against Crimo. Highland Park Police notified state police about the visit. At the time, involuntary commitment wasn't an option, Covelli said.

The local police submitted a "Clear and Present Danger" report about the visit to the Illinois State Police, the agency said.

"The report indicates when police went to the home and asked the individual if he felt like harming himself or others, he responded no," state police said in a second statement.

"Additionally and importantly, the father claimed the knives were his and they were being stored in the individual's closet for safekeeping. Based upon that information, the Highland Park Police returned the knives to the father later that afternoon," state police added.

State Police Master Sgt. Delilah Garcia said they looked at whether Crimo had a firearm owner's identification (FOID) card that should have been revoked, but he had no card.

In a news release, Illinois State Police officials said Crimo in December 2019 applied for a FOID card that was sponsored by his father.

"The subject was under 21 (he was 19) and the application was sponsored by the subject's father. Therefore, at the time of FOID application review in January of 2020, there was insufficient basis to establish a clear and present danger and deny the FOID application," state police said.

In April 2019, local police went to the family home after receiving a report Crimo had tried to take his own life a week earlier. Officers spoke with him and his parents and were told mental health professionals were handling the matter, Covelli said.

Covelli said later that the suspect bought five guns, including two rifles, after the September visit from police.

The suspect legally purchased the weapon he used in Monday's shooting, Covelli said Tuesday, describing it as a "high-powered rifle" which shot high-velocity rounds. The weapon, which he described as "similar to an AR-15," was purchased locally, Covelli said, within the Chicagoland area.

Investigators believe he fired more than 70 rounds over the course of the attack, Covelli said, and there is no indication the weapon was modified.

Crimo also legally purchased a second rifle found in his vehicle at the time he was apprehended, as well as other guns recovered from his home, which Covelli described as pistols.

Between June 2020 and September 2021, Crimo passed four background checks while purchasing firearms. Those background checks went through the Firearms Transaction Inquiry Program (FTIP), which includes the National Instant Criminal Background Check System, state police said in their statement.

At the time, the only criminal offense included in Crimo's history was a January 2016 ordinance violation for possession of tobacco, and no mental health prohibitor reports were submitted to state police by healthcare facilities or personnel, police said.

Police in Highwood -- the suspect's hometown, just outside Highland Park -- had no prior crime-related interactions with Crimo, according to Chief Dave Wentz.

The only contact the department had with Crimo involved a noncriminal incident where Crimo was present when he was a juvenile, Wentz said.

"We literally have nothing on him," Wentz said. "He was not potentially involved in anything."

The suspected shooter posted music on several major streaming platforms under the pseudonym Awake the Rapper, and he apparently made and posted music videos online featuring ominous lyrics and animated scenes of gun violence.

In one video titled "Are you Awake," a cartoon animation of a stick-figure shooter resembling the suspect's appearance is seen wearing tactical gear and carrying out an attack with a rifle. Crimo, seen with multicolored hair and face tattoos, narrates, "I need to just do it. It is my destiny."

In another video titled "Toy Soldier, a similar stick-figure resembling the suspect is depicted lying face down on the floor in a pool of his own blood, surrounded by police officers with their guns drawn.

Law enforcement is reviewing the videos posted online, Covelli said at Tuesday's news conference, noting police had not previously been made aware of them. "We'll look at them and see what they reveal."

Several of the suspect's online postings "reflected a plan and a desire to commit carnage for a long time in advance," Mayor Rotering said in an interview with NBC's Hoda Kotb on "Today.

"And it's one of those things where you step back and you say, what happened? How did somebody become this angry and hateful," she said, "to then take it out on innocent people who literally were just having a family day out?"

YouTube and Spotify removed content tied to the suspect from their platforms, the companies confirmed Tuesday. They declined to answer questions about whether the content had been flagged or previously reported for violations of their respective terms of service. The companies also declined to say precisely when they removed the suspect's content.

CNN has also reached out to Apple Music, Amazon Music, Tidal and Pandora with similar questions, but the companies have not yet responded.

Highland Park Mayor Nancy Rotering knew the suspect when she was his Cub Scout pack leader, she said, telling CNN, "Many years ago, he was just a little boy, a quiet little boy that I knew."

"It breaks my heart. I see this picture and through the tattoos, I see the little boy," she said. "I don't know what got him to this point."

The suspect's uncle, Paul A. Crimo, was "heartbroken" to learn his nephew was believed to be responsible for Monday's shooting, telling CNN," There were no signs that I saw that would make him do this."

The suspect lived in an apartment behind a house in Highwood, owned by his father, said Paul Crimo, who also lives at the house. He last saw his nephew Sunday evening, he said, sitting on a recliner in the house and looking on his computer.

"Everything was as normal," he said.

To Paul Crimo's knowledge, his nephew did not have a job, he told CNN, though he worked at Panera Bread before the Covid-19 pandemic. Paul Crimo said he had never seen the suspect engage in violence or concerning behavior. He didn't know of his nephew's political views, either, describing him as a "quiet" person.

"He's usually on his own. He's a lonely, quiet person. He keeps everything to himself."

The suspect's father and Paul Crimo's brother, Robert Crimo Jr., previously ran for mayor, he said. "We are good people here, and to have this is devastating."

"I'm so heartbroken for all the families who lost their lives," Paul Crimo said.