What we know about Robert 'Bobby' Crimo III, the suspect in Highland Park parade massacre

The 21-year-old suspect in the mass shooting at a Fourth of July parade in suburban Chicago that left seven dead and more than 30 wounded is an aspiring rapper with an apparent trail of violent social media posts that investigators are combing through.

Multiple law enforcement officers detained Robert "Bobby" Crimo III at gunpoint following a car chase hours after Monday's massacre in the North Shore town of Highland Park.

Investigators are poring over social media posts on numerous platforms, including Instagram, Snapchat, Twitter, TikTok, YouTube and Discord, which they believe are associated with Crimo.

Lake County Sheriff's Office officials said at a news conference Tuesday that the investigation alleges that Crimo planned the attack for several weeks and opened fire on paradegoers from the roof of a business he accessed by an affixed ladder. Police alleged that Crimo fired more than 70 shots during the episode.

He was dressed in women's clothing, apparently to blend in with the panicked crowd as he made his getaway, said Lake County Sheriff's Sgt. Christopher Covelli.

Covelli said Crimo legally purchased the high-powered AR-15-style rifle he allegedly used in the attack in Illinois. Covelli said a second rifle, also purchased legally, was found in the car Crimo was driving.

He said Crimo also legally bought three other weapons, including two pistols, that investigators seized from his father's home.

The Illinois State Police said that at the age of 19, Crimo passed four background checks to purchase weapons after applying for a firearm owner identification card in December 2019. Because he was under the age of 21, his father sponsored his application and at the time it was reviewed "there was insufficient basis to establish a clear and present danger and deny the FOID application," the state police said.

The state police said that before they approved Crimo's FOID application, they reviewed his criminal history and only found a January 2016 ordinance violation for being a minor in possession of tobacco.

Crimo was approved for a gun license despite two troubling run-ins with police that apparently did not surface in his background checks. At a news conference Tuesday afternoon, Covelli said police checked on Crimo after he attempted suicide in April 2019, but no action was taken after his parents assured officers Crimo was getting help from mental health professionals.

Covelli said police were called to Crimo's home in September 2019, about four months before he applied for a FOID card, by a family member who claimed Crimo allegedly threatened to kill everyone in his house. He said no charges were filed in the incident when his family declined to press charges, but police seized 16 knives, a dagger and a sword from Crimo and reported the incident to the Illinois State Police.

Sgt. Delilah Garcia of the Illinois State Police said no action was taken against Crimo in the September 2019 incident. She said at the time Crimo was not in possession of any firearms and did not have a FOID card or a pending application for one to revoke.

The Lake County Sheriff's Office has told its law enforcement partners that Crimo is answering investigators' questions and has made statements taking responsibility for the attack, according to multiple law enforcement sources.

Lake County State's Attorney Eric Rinehart announced Tuesday afternoon that Crimo has been charged with seven counts of first-degree murder. Rinehart said more charges are expected.

State police said Wednesday there will be a criminal investigation into the culpability of Crimo's father because he signed the FOID affidavit.

Steve Greenberg, an attorney for Crimo's parents, said the family has retained two lawyers, Tom Durkin and Josh Herman, to represent their son. There was no immediate comment from the defense attorneys and Greenberg said it was unclear if the lawyers have yet met with the suspect.

"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. Our hearts, thoughts, and prayers go out to everybody," Crimo's parents said in a statement Greenberg released Tuesday afternoon.

The lawyer added, "The parents request that all respect their privacy as they try to sort thru this tragedy."

The suspect lived with his uncle, Paul Crimo, who told ABC News that he has been interviewed by the FBI. Paul Crimo told ABC News that while his nephew lived with him, they rarely had conversations. He said his nephew mostly focused on his music and stayed in his room and on his phone.

He said his nephew never espoused political views or mentioned weapons or firearms. He said his nephew didn't have a job or many friends.

He said he last spoke to his nephew around 5 p.m. Sunday, but they just said hello while passing each other in the home they shared in the North Shore town of Highwood.

The uncle said his nephew was driving his mother's car when he was taken into custody. He said his nephew's car was still parked in front of his home on Tuesday. The car has a number 47 decal on the driver's side door, matching a tattoo on his face.

A law enforcement source briefed on the case told ABC News Tuesday that investigators have identified posts from several social media platforms alleged to be tied to Crimo that discuss or depict acts of violence -- including shooting people.

The Institute for Strategic Dialogue, which monitors and analyzes extremist content online, said in a briefing statement that it appears Crimo had an extensive online presence and that posts allegedly associated with him included mental health issues, hatred and a gravitation toward far-right and neo-fascist thoughts and ideologies.

One online post allegedly made by Crimo about 10 months ago includes a video that appears to be a portion of the Fourth of July parade route in Highland Park that was accompanied by music with a death theme, according to Strategic Dialogue.

Crimo, according to Strategic Dialogue, appears to have created videos that depicted mass shootings, as well as his own death. One video Crimo is believed to have posted portrays the aftermath of a school shooting and another uses animated figures to depict a mass shooting that mimicked the crime, according to Strategic Dialogue.

The posts believed to be from Crimo also include an online symbol for himself resembling a hate symbol associated with neo-Nazis, according to Strategic Dialogue. Similarly, Crimo's content features the aesthetics of niche neo-fascist subcultures, the group said.

"He was not just crying out for help, he was screaming out for it," said John Cohen, an ABC News contributor and the former acting undersecretary for intelligence and counterterrorism coordinator at the U.S. Department of Homeland Security.

Covelli said Crimo was identified through surveillance video and by tracing the gun he allegedly left at the scene. Investigators also have not commented on a possible motive for the mass shooting.

Meanwhile, the wife of the rabbi at Chabad House in Highland Park told ABC News that Crimo came to their Passover service this year. She said Crimo left on his own after his presence raised concerns at the synagogue.

The synagogue now has armed security, given the heightened concerns of violence at religious institutions around the country.

Covelli said at Tuesday's news conference that investigators have not unearthed any evidence suggesting a racial or religious motivation for the rampage.

Crimo was taken into custody more than eight hours after the Highland Park rampage when an all-points bulletin was issued naming him as a person of interest and describing the 2010 silver Honda Fit he borrowed from his mother. A North Chicago police officer spotted the car on U.S. Route 41 and attempted to stop Crimo, who led police on a brief chase before stopping and surrendering, authorities said.

Crimo was apparently raised in Highland Park, where his father, Robert Crimo Jr., owns a delicatessen.

Crimo's father ran for mayor of Highland Park in 2019, but was handily defeated by incumbent Mayor Nancy Rotering, according to election results.

A Highland Park business owner who grew up with the elder Crimo told ABC News that he was "trying his hardest to help his community" but "probably didn't have that much of a chance."

Following Monday's shooting, Rotering spoke of the tragedy during a news conference.

"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," Rotering said.

Heavily tattooed, including inked patterns on his face, neck and hands, Crimo was an amateur rapper who went by the stage name Awake the Rapper. One music video posted on YouTube appears to depict the aftermath of a school shooting in which Crimo is filmed alone in a classroom dressed in a helmet and bulletproof vest. A separate video shows Crimo sitting on a bed rapping while a newspaper featuring Lee Harvey Oswald hangs on the wall behind him.

Another video allegedly posted by Crimo shows a cartoon depiction of a person aiming a long gun at other characters with their hands up and on the ground, and a character wearing a shirt with a logo used on Crimo's alleged social media accounts. The video also shows a cartoon character being shot by police.

Law enforcement sources told ABC News that Crimo's music often referenced death and dying.

Spotify, where Crimo had a little over 16,000 monthly listeners, and Apple have removed Crimo's accounts and music.

A YouTube spokesperson said in a statement to ABC News, "Following the horrific incident in Highland Park, our Trust and Safety teams identified and quickly removed violative content, in accordance with our Community Guidelines."

ABC News' Aaron Katersky and Stephanie Wash contributed to this report.