CHICAGO - The Highland Park Independence Day parade shooting suspect Robert Crimo III's mother had a troubled past marred by abuse allegations against her ex-boyfriend and other run-ins with the law, according to court documents.

Denise Pesina, 48, also allegedly left Crimo III, 21, in a hot car when he was a toddler and completed 100 hours of community service for driving under the influence in 2012. 

Lake County court documents shed additional light on Crimo III's troubled childhood and his mother's tumultuous past.

On Monday, the 21-year-old was accused of killing at least seven people and injuring dozens more after climbing on top of a roof above a July Fourth celebration and then opening fire.

HIGHLAND PARK FOURTH OF JULY SUSPECT GREW UP WITH BOOZY PARENTS WHO OFTEN CALLED 911 TO HOME: DOCUMENTS

Robert Crimo III's arrest

Police arrest 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. (Associated Press/ Katherine Rappel/ Highland Park Police)

"If you're growing up in that kind of traumatic environment, it can create an imbalance," said John Kelly, a criminal profiler and psychotherapist who has interviewed numerous killers. "There's no question about it."

He said early childhood is most important to a person's formative years, but brain development can continue into their mid-20s.

In August 2002, when Crimo III was a toddler, Pesina allegedly left him in a hot car for 27 minutes while shopping at Toys ‘R Us.

"Defendant left Robert Crimo III unattended in a motor vehicle while the motor vehicle was parked in a Toys R-US (sic) parking lot, 1610 Deerfield Road, Highland Park, Lake County, Illinois, for about 27 minutes, while the windows were rolled up, the car was off and the temperature outside was about 79," the warrant reads. He was 2 at the time.

Police report involving Denise Pesina, Robert Crimo III's mother

In August 2002, when Crimo III was a toddler, Pesina allegedly left him in a hot car for 27 minutes while shopping at Toys ‘R Us. (Fox News Digital)

That landed her a conviction for endangering the life or health of a child, a Class A misdemeanor.

"If nobody cared about him as a child growing up, then he didn’t have that empathy," Kelly told Fox News Digital Friday. "Why does he have no remorse or no guilt or no empathy for other human beings? I’ve seen this in a lot of serial killers, because they were abused."

And in 2012, Pesina was sentenced to a year of probation and 100 hours of community service for driving under the influence after getting pulled over with a flat tire and a BAC of .21%. She had a "strong odor of alcohol on breath and failing [field sobriety tests]," a police officer wrote in a report at the time.

HIGHLAND PARK FOURTH OF JULY SHOOTING: A TIMELINE OF EVENTS

She completed her community service in "a very commendable fashion with a good attitude," according to a letter from her supervisor.

Robert Crimo III is accused of a mass shooting in Illinois

A photo illustration of accused July 4 shooter Robert Crimo III with his father, Bob Crimo (left) and mother Denise Pesina (right). (FBI handout/Facebook)

The charges are in addition numerous 911 calls to the Illinois family’s home on McDaniels Avenue, in which the parents repeatedly blamed each other for verbal arguments. Many of the disputes ended with Robert Crimo Jr., Crimo III's father, leaving for the night, either voluntarily or at the request of police, and he was arrested at least once.

HIGHLAND PARK FOURTH OF JULY PARADE ATTACK: SHOOTING SUSPECT'S FATHER NOT IN THE CLEAR YET, POLICE SAY

One shocking case came before Crimo III was born involving Pesina's ex-boyfriend, Steven Brown.

In 1999, Pesina sought an order of protection against Brown, whom she accused of sexually assaulting her 4-year-old daughter, Crimo III's half-sister. The girl's father had previously died of carbon monoxide poisoning, according to court documents. She also had to sue to establish paternity so that the child could have a share of her father's estate.

The mother and daughter each went to counseling, and Pesina spent time hospitalized "due to the physical abuse of Steven Brown." Pesina also alleged that Brown harassed her and her daughter by making "unwanted phone calls and appearances at their place of residence."

Denise Pesina allegations against Steven Brown

Denise Pesina's allegations of harassment and abuse against her former boyfriend, Steven Brown, in 1999. (Fox News Digital)

Pesina had other issues with men besides her husband while Crimo III was growing up.

A man named David Daniels is named in several police reports at the family’s home, claiming to be Pesina’s "boyfriend," which she disputed. 

She also accused a neighbor, William Hollander, of making unwanted advances to her, and Crimo Jr. called police one night to tell them the neighbor gave his wife a bottle of wine.

Police also visited the family home twice in 2019 due to alleged threats made by Crimo III, although his parents declined to file complaints and no crimes were charged.

Had police or the parents had intervened then, Kelly argued, Crimo III may not have been able to legally purchase the four firearms he later picked up, including the Smith & Wesson M&P 15 rifle that he allegedly used during the massacre.

Robert Crimo III allegedly opened fire on a Highland Park parade

A photo combination of allegeded July 4 parade shooter Robert Crimo III (right) and his mom Denise Pesina. (Facebook/FBI)

"The way it usually works is he would’ve been arrested, he would have to get a lawyer," Kelly said. "The prosecutor would have said, ‘Get him into counseling and get us some reports on him. We want to make sure he’s not a danger.' … He would’ve been evaluated for mental health, and at that point in time, I don’t know if he would have still been able to buy the rifle."

CLICK HERE TO GET THE FOX NEWS APP

The first incident, in April, came after Crimo III allegedly threatened to kill himself. The second was for threats to kill his family. Later that year, he applied for an Illinois Firearm Ownership ID with his father's sponsorship.

"I've seen this a million times, where alcoholic parents then feel guilty because they were drinking and carrying on and fighting and everything while raising the kid, and their guilt causes them to be enablers," Kelly, the criminal profiler, said. "And what that all means with him is, I don’t know everything because all the information isn’t out there, but that could create a situation where the father would be enabling him by helping him purchase the rifle."