The suspect in the Highland Park, Illinois, Fourth of July mass shooting was flagged by police as a "clear and present danger" in 2019, authorities said Tuesday.

Robert "Bobby" E. Crimo III, 21, the suspect in the mass shooting that killed seven people and wounded dozens of others at a Fourth of July parade, was still able to clear state-required background checks to purchase firearms on at least four separate occasions between 2020 and 2021, the Illinois State Police said.

A portrait of Robert “Bobby” E. Crimo III as a mysterious and music-obsessed loner began emerging Tuesday, a day after he was arrested in the wake of a mass shooting at a July Fourth parade that left seven dead and traumatized an affluent Chicago suburb.

Crimo, 21, who attempted to disguise himself by wearing women's clothing during the deadly rampage, aspired to be a rapper and his music got darker and more delusional as he got older and relationships with his parents and a girlfriend frayed, former friends said.

“He was in his own world,” said 22-year-old Nick Pacileo.

The man charged with killing seven people at a Chicago-area July Fourth parade slipped past the safeguards of an Illinois "red flag" law designed to prevent people deemed to have violent tendencies from getting guns, officials revealed on Tuesday.

The disclosures raised questions about the adequacy of the state's "red flag" laws even as a prosecutor lauded the system as "strong" during a news conference announcing seven first-degree murder charges against the 21-year-old suspect, Robert, E. Crimo III.