Updated 05/27/14 – 5:35 p.m.

WAUKEGAN, Ill. (CBS) — A teenager accused of huffing computer cleaner before running over a 5-year-old girl two years ago has pleaded guilty to reckless homicide, but still faces trial for aggravated DUI charges.

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Carly Rousso, 19, has opted for a bench trial on a felony charge of aggravated DUI resulting in death, after failing to reach a plea agreement with Lake County prosecutors in the death of 5-year-old Jaclyn Santos-Sacramento.

Prosecutors have said Rousso huffed an aerosol can of keyboard cleaner on Labor Day 2012, before plowing her parents’ Lexus into the Sacramento family on a sidewalk in Highland Park. Five-year-old Jaclyn Santos-Sacramento was killed in the crash. Her mother, Modesta Sacramento-Jimenez, and two brothers also were injured.

CBS 2’s Mike Puccinelli reports Rousso pleaded guilty to a count of reckless homicide before her bench trial began on Tuesday, but prosecutors wouldn’t budge on a more serious charge of aggravated DUI, which carries a sentence of up to 14 years.

The defense has challenged the aggravated DUI charge is unconstitutional, because the aerosol cleaning agent Rousso allegedly inhaled before the crash was not specifically mentioned as an intoxicant in the law.

Assistant Lake County State’s Attorney Michael Ori said Rousso lost control of the car after huffing Blast Away, a computer cleaner containing difluoroethane, a chemical compound that can have a similar effect to alcohol when inhaled.

“There is no ambiguity in this statute. The statute is as ambiguous as the defendant’s intentions in inhaling the Blast Away, and there is no ambiguity regarding the defendant’s intentions.”

However, Defense attorney Douglas Zeit argued difluoroethane is not covered by Illinois DUI laws, or in half a dozen other states.

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“None of which, judge, had difluoroethane on any list of compounds that was illegal,” he said.

Prosecutors played recordings of 911 calls, and videotape of the actual collision as they presented their case on Tuesday. After the initial impact, the Lexus bounced off two walls, and ran over the family two more times. They also played a video of Rousso’s statement taped in her hospital room hours after the accident.

Jaclyn Santos-Sacramento

Jaclyn Santos-Sacramento, 5, was hit and killed by a car in Highland Park Monday. (Credit: CBS)

Prosecutors said it all happened because Rousso wanted to get high.

“It was at this point, somewhere between leaving the Walgreens store on Deerfield, and the parking lot near 757 Central Avenue, that she lost consciousness, turned her car across lanes of oncoming traffic, up over a curb, down a sidewalk, and directly into Modesta and her children,” Ori said.

Zeit said prosecutors would fail to prove Rousso is guilty of aggravated DUI.

“She is clearly guilty of the reckless homicide, judge. And again let there be no question, we think that was a horrendous, horrendous thing,” he said.

Three witnesses testified for the prosecution Tuesday morning, including two people who tried to assist in the immediate aftermath of the collision, and a police officer who responded to the five 911 calls made in the case.

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Closing arguements are set for Thursday afternoon.