CHICAGO (CBS) — An Arlington Heights man has been charged with driving under the influence in a fatal crash on the Eisenhower Expressway earlier this week.

Illinois State Police said 35-year-old Matthew Graff was driving a 1993 Chevrolet motor home in the westbound lanes of the Eisenhower Sunday afternoon, when he slammed into the back of a 2005 Nissan sedan that had stopped on the right shoulder near Mannheim Road.

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Matthew Graff is charged with two counts of aggravated DUI, in a crash that killed a 34-year-old man and seriously injured a 42-year-old woman on the Eisenhower Expressway on May 6, 2018. (Credit: Illinois State Police)

The driver of the Nissan, 34-year-old Eduardo Moreno, of Berwyn, was taken to Loyola University Medical Center, where he was pronounced dead. Moreno’s passenger, a 42-year-old woman, was seriously injured, but expected to survive.

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Police said Graff was taken to Elmhurst Hospital, but his injuries were not life-threatening.

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Investigators said Tuesday they believe drugs were a factor in the crash. Graff has been charged with two felony counts of aggravated DUI. Police did not say whether the charges involved the use of drugs or alcohol.