The alleged gunman accused of killing seven people at an Independence Day parade in the upscale Chicago suburb of Highland Park confessed to the shooting Wednesday and had plans for a second attack, according to authorities

Robert E. Crimo III, 21, had been charged Tuesday with seven counts of murder. He appeared in a Chicago-area court via Zoom on Wednesday and heard the charges read against him.

He will likely face many more counts for the Monday attack that left dozens wounded. If convicted, Crimo will face the possibility of life in prison without the possibility of parole.

"He went into details about what he had done. He admitted to what he had done," Lake County State’s Attorney Eric Rinehart told reporters.

Rinehart said he did not want to speculate on the motive of the shooting.

The judge presiding over the case ordered Crimo to be held without bail and scheduled a preliminary hearing for July 28.

On Monday, the gunman took up a position on a rooftop overlooking the parade and fired on the crowd with an assault rifle. After the attack, he appeared to dress like a woman as a way to blend into a crowd of terrified bystanders to make his escape.

The shooting sparked an hours-long manhunt that ended with Crimo being apprehended by police at a traffic stop. In total, the rampage left seven dead and 47 wounded.

Police have said that they have not yet seen evidence of racist, religious or "other protected status" motivation. Instead, investigators have learned that Crimo has a troubled past that has included run-ins with law enforcement before.

Former friends who knew Crimo told NBC News that he had exhibited anti-social behavior and distanced themselves from him.

Some described Crimo as depressed and that he had abused psychedelic drugs, particularly after a break-up with a former girlfriend. He also had posted racist rants over social media. Crimo maintained an online presence where he shared his own music that invoked violent imagery that worried those around him.

Police had two encounters with Crimo in 2019. One involved a police visit to the family home after he threatened to commit suicide. In September 2019, police responded to a call to the Crimo family home after he threatened to "kill everyone" and confiscated a collection of bladed weapons from him.